&1: &2

What causes this issue?

For &V1&, the overhead costs (&V2&) are negative. This means that the
plan value for investment costs is greater than the plan value for
combined costs. This is an error, since investment costs are by
definition a part of combined costs.
The system offers an automatic correction option. Choose the 'Correct
plan values' function. Specify whether you want the system to derive
combined costs from the investment costs, or the investment costs from
the combined costs.
&NOTE&
This applies only to those years (overall) for which the overhead costs
are negative.

Error message extract from SAP system. Copyright SAP SE.