Don't override anything.
Enter the assets according to the proper depreciation schedules (the results of the Cost Seg), and using the proper "prior depreciation" that would have been used if you had been doing that all the time (if you leave the "prior depreciation" BLANK, the program will assume the prior years were correct). That will give you the proper current-year depreciation.
As for Form 3115, the calculated results of that is entered as an 'other' or 'misc' deduction on the form that reports that activity.
