In the MDT a node of installation facts is defined as follows (example):
It is expected that the operand will be created with a valid-from and valid-to as CONTSTART.
But that's not the case: The operand is created with valid-from and valid-to of contract.
This is valid for all kinds of installation facts (except FACTOR) and will also affect handling during move-out or product change.
It's because the generation period is weighted higher than parameter definition of attribute.
In such a case the AB and BIS needs to be either defined as virtual attributes or as of note 1788494 Function Module ISU_PDSCR_INST_FACTS_MODIFY_P can be used.
This one needs to be replaced in the respective master data template categories (in table EPDTYPE).