Conversion of Activity Numbers (COI)

It would be greatly appreciated if anyone would please provide any information regarding what/how BCS programs use the Activity Numbers ODS. Is this information only relevant for each period, or is it somehow used in subsequent periods?

We are in the process of converting a BCS 3.5 system to BCS 6.0 via reimplementation to a completely new BW/SEM environment. Our plan for conversion is to take the existing data from totals into the new system along with the other ODS (with some mapping to reduce the number of profit centers).