Hi Martin/Raj,
If you update through customer exit to both F-Fact anf E-Fact tables, SID inconsistency issues will be raised. It will be tedious to create SIDs for these modified records.
Let's say he updates the data to cube through cust exit, what is he going to do with Aggregates?
To avoid all this mess, it's advisable to drop the Aggegates and Cube. make the change in the transformation rule and load all the data freshly to cube. There will not be any inconsistencies in the future. Hope you understand , Why did I say like that.
Regards,
Suman