Impacts of Amendment effective date on Contract

We have a Project Process Configurator defined for both the Bill Plan and Revenue Plan, based on which automatic events are generated. I would like to understand the behavior when a contract amendment is performed.

For example, if a contract amendment has an effective date of 27‑Feb, and an expenditure item dated 26‑Feb is created, then the Generate Invoice process is run—an automatic event is still created for that expenditure item even though its date is prior to the amendment effective date. Does this imply that the amendment effective date is driving or processing - creation date rather than the expenditure item date?