Submitting construction credits at design final review stage

You will need to wait until the Construction Preliminary Review to upload construction credits. Even if you submit the construction credits in the Design Final Review the GBCI will not review them.

And even if you could submit the construction credits in the Design Final Review, I wouldn't recommend it. Turning credits in during a Final Review misses the opportunity for the reviewers to provide Preliminary Review comments and the design team the ability to respond in turn without additional fees.

Only Design credits can be submitted during the Design (Prelim & Final) review.  During the Construction review you submit all your desired Construction credits, and any desired Design credits that you weren't able to submit during the Design review. 

If you have any Design credits that were already reviewed and approved during the Design review phase but went through enough changes to change compliance level/strategy, they should be re-submitted for review.  If some changes between design and construction resulted in (as an example) improved water reduction rate, you want to get credit for that!  Maybe part of the project was removed after the Design review, based upon project costs, etc. - this changes the scope of the project and affects your calculations, etc. that were done during the Design phase, and should be re-reviewed with the updated information.

BTW there is no problem with uploading docs or working on the Construction Credits early. Just don't click the "Ready to Review" button and turn the grey checkmark green until you have completed and accepted the final Design Review.