I don’t see someone here says it make sense or not burning @2x with 716a.
I thought you come here for help and people here trying to help, however you did not respond or respond with minimum information only, ie: “4 consumer players and 3 softwares”, or “Yes, i’ve run all kind of test”. Regular cdfreak members actually know what kind of software that can conflict our burners, however we can’t help you that way.
BTW, I would burn those 400 2x rated disks in the BTC. Save the 716a for better media that can be burn excellent at 8x, 12x or 16x.