Hi Abhishek,
I understand your points and business challenges. However as this is the cut-over requirement as you are transforming the business processes from IO to Projects, there has to be change management process in place which guides and educates the business.
What I may suggest is -
Approach #1: Transform all existing IOs and AUCs to Projects as I suggested in my earlier response.
Approach #2: Keep all existing IOs and AUCs as is in the system. Try to close most of them by Sep-2016. (I understand not much time left). Then all new CAPEX work from Oct 2016 should be covered via Projects. This way business can identify which all are legacy (not really legacy but the ones with older methodology) AUCs / Assets and which all are new ones.
Hope this helps.
Best regards,
Aditya