Hey @George McElfresh - We see this type of thing a lot. ITP is a great planning tool, but sometimes you can't compare apples to apples without a little CT mapping help.
We have had to pull data from ITP into CT to leverage lookups and lookupexs to finalize the allocations or bring in additional attributes.
While this process is relatively simple, there are a few things you may run into:
1) Design the process so that it is repeatable and well documented.
2) Because you are going to be re-importing your plan from CT into ITP, you will lose some of the functionality as everything is going to end up on the Other tab. If you are using this purely for reporting, and won't need to adjust the plan or leverage for a baseline, then you are good to go.
@Chrystie Lambert leverages a process like this for their budget process, and may be able to give some additional insights into the things to keep in mind.
Thanks,
Ryan