Different activity prices are not supported for &/&

What causes this issue?

You have activated the average activity price indicator for plan
version &V3& in fiscal year &V4&.
However, different values have been planned for cost center/activity
type &V1&/&V2&.

System Response

The data cannot be processed.

How to fix this error?

Move to the period screen for the cost center/activity type combination
and correct the values so that the same activity price is defined for
all periods.

Error message extract from SAP system. Copyright SAP SE.