Calculated amount is too large

What causes this issue?

Calculated amount &v1& is greater than the maximum amount that can be
entered in the internal field for saving the net amount. This message
issued to avoid a runtime error.
This large amount can be caused by a very large
billing quantity, an extremely high price amount, or an
extremely long billing period (for time-dependent variables).

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Check the variables that form the basis
of billing. An incorrect dimension in the billing quantity could be the
cause (GWh instead of kWh). Normally, there is more than one cause for
this error.
If the basic variables are correct, try to keep the amounts in
each individual bill small by shortening the billing periods.

Error message extract from SAP system. Copyright SAP SE.