Many companies rely on wallboxes with MID meters when charging company cars at home. The expectation is straightforward: if the measurement is accurate, the billing should be correct as well.
However, this is exactly where several misconceptions arise in practice (in Germany).
Misconception 1: “An MID meter is sufficient for legally compliant billing”
This is by far the most common misconception.
An MID meter ensures that electricity consumption is measured accurately. What it does not automatically provide is a legally compliant classification of this data within the context of reimbursement to the employer.
This background is often underestimated: a measurement only answers the question of how much electricity was consumed. For billing purposes, this alone is not sufficient, as it must also be assessed who the consumption can be attributed to and under which conditions it occurred.
An MID meter cannot determine:
whether a charging session was business or private,
whether multiple users were involved,
whether the recorded values were transferred without alteration,
or how this data was incorporated into the billing process.
For companies, this means: the meter provides an important basis. Whether this data is sufficient depends on whether it is used within a process that is consistent, transparent, and fully traceable.
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Misconception 2: “If the measurement is correct, the billing is automatically correct”
This assumption mixes two different layers.
Measurement answers the question of how much electricity was charged. Billing, however, must additionally clarify who the consumption is assigned to and on what basis reimbursement is made. Without a clear allocation, it cannot be proven whether the costs were actually incurred for business purposes. As a result, even correctly measured values lose their relevance.
It is also important to consider the transmission and separation of charging sessions. MID meters provide legally accurate measurement values but only display a continuously accumulated meter reading. They do not provide a way to assign energy volumes to individual charging sessions in a legally compliant manner. In addition, only the display of the meter is conformity assessed, not the data interfaces. These interfaces are purely informational and must not be used for billing purposes. As a result, the only option is manual reading of the display.
Misconception 3: “Manual processes are sufficient”
Manual processes are not excluded in principle and can work in practice, particularly in smaller setups or with only a few relevant charging events.
However, the key point is that manual solutions must meet the same requirements as automated processes. This includes ensuring that all recorded data is complete, accurate, and traceable at any point in time.
As the number of users and charging sessions increases, the effort grows significantly. Values must be recorded, verified, and transferred regularly. Follow-up questions arise when data is incomplete or implausible, and corrections need to be documented transparently. What initially appears to be a simple solution quickly turns into a time-consuming process.
In addition, manual workflows are more prone to breaks in traceability. Values are transferred instead of automatically recorded, changes are not systematically documented, and individual steps are difficult to reconstruct afterwards.
Manual solutions are therefore fundamentally possible but often reach their limits in practice, especially when consistent and audit-proof documentation is required.
Misconception 4: “Billing at home is less strictly regulated”
This is frequently underestimated.
Even though charging takes place in a private environment, reimbursement by the employer is still a billing-relevant process, subject to different regulatory frameworks.
On the one hand, there are tax regulations defined, for example, by the German Federal Ministry of Finance (BMF). These determine under which conditions reimbursements are permitted and how they are treated.
On the other hand, the requirements of calibration law (Mess- und Eichrecht) govern how measurement values may be collected and used in billing contexts. There is a certain degree of simplification that allows the use of MID meters. However, this comes with specific conditions:
the energy must be measured with a meter permanently connected to the grid that exclusively records the electricity supplied to the electric vehicle, meaning no other consumers are connected,
the electricity must be used by a single contractual partner,
and the meter must comply with general calibration requirements, meaning it is conformity assessed or properly calibrated and used correctly.
(cf. “Requirements for measuring devices for reimbursing home charging costs ” by the AGME)
For companies, this means that billing does not take place in an unregulated environment but within a framework of different regulations addressing different aspects. As a result, not only the measurement itself is relevant, but also how the data is recorded, assigned, and further processed.
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Misconception 5: “The BMF letter covers everything – calibration law no longer matters”
This misconception has increased significantly this year.
It is based on the BMF letter dated November 11, 2025 , which provides guidance on the tax treatment of charging company cars at home. Many conclude that this resolves the topic entirely.
This is exactly the misunderstanding. The BMF letter primarily addresses the tax perspective, namely under which conditions reimbursements are permissible and how they are treated.
It does not replace other regulatory requirements. In particular, the rules governing measurement and billing of electricity remain in place and are monitored by the relevant authorities within the framework of calibration law.
At the same time, practical experience shows that home charging often differs from typical public charging scenarios. In certain cases, it is treated more like private electricity consumption. Nevertheless, proper and traceable measurement remains the foundation of correct billing.
For companies, this means: the BMF letter provides clarity on one level but does not automatically resolve all requirements arising from other regulations.
An MID meter may ensure accurate measurement, but it does not automatically fulfill the requirements related to the practical implementation of billing. This includes, in particular, the clear allocation of charging sessions, reliable processing of measurement values, and full traceability of the data throughout its lifecycle.
Publications and statements from relevant authorities also confirm that calibration law requirements continue to apply independently of tax regulations. The risk therefore does not arise from individual rules, but from the assumption that one regulation overrides all others.
What this means in practice
When these misconceptions are considered together, a clear pattern emerges: the focus is often placed on the hardware, while the actual billing process receives too little attention. A robust solution must therefore do more than just measure correctly.
It must ensure
that charging sessions are clearly assigned,
that data is recorded automatically and without alteration,
and that all steps remain traceable, even retrospectively.
Only this combination creates a foundation that holds up beyond day-to-day operations.
Practical perspective
At this point, it becomes clear why purely MID-based measurement solutions reach their limits in practice. The decisive factor is not only the measurement itself, but how it is embedded in a consistent and reliable billing process.
In practice, companies increasingly rely on systems that combine measurement, allocation, and billing while also addressing requirements for traceability and consistency, particularly in light of regulatory frameworks such as calibration law.
Solutions like the Charge Repay Service address exactly this challenge. They ensure that charging sessions are clearly assigned, measurement data is structured and processed, and the entire data lifecycle remains transparent over time. This creates a foundation that not only relies on accurate measurement values but also meets the requirements associated with billing in a corporate context.
