I wonder if you could cite the source on that. I found no bulletin and the 737 FM still requires it to be operable before Entry and confirmed ON in the ETOPS a before takeoff checklist. I did hear they're working with the FAA to remove the requirement but haven't seen the allowance for it in any of our governing documents. Not that anyone would use APC for operating guidance.

"Due to the limited time that the 737 can operate on standby electrical power it is required that the APU be run continuously in ETOPS airspace. The policy for ETOPS flights is to start the APU on the ground and leave it running until past the Extended Range Exit Point (EXT)."