Identifying if an assignment change was done with a future, retro or current date

Summary

Having trouble finding a way to identify if an assignment change was done with a future date or retro date after the fact.

Content

Hello,

My team is in the process of implementing HR Reports for a client on 18B. We have a requirement to create a BIP or OTBI report displaying each employee's assignment change history within a period and on each row identifying if the change was sent with a future date or a past date at the time. We can't find a way of doing this using the fields available in Assignment Event Realtime Subject Area or the accessing the tables directly. This is a common requirement that we expect our other clients will have when migrating to HCM.