If you want to keep the 2 year warranty, you can only flash your drive with a firmware starting with G7*9.
There will come a G7T9 for Benq oem.
The thread you are referring to is about "G"7P9 firmware and not "B"7P7.
The only difference between "G" oem and "B" Benq firmware are the name strings.
You will get the same excellent burn quality with a "G" firmware as a "B".
I first burned with G7P9 from NU-Tech, before I voided my warranty and switched to B7P9.
The burn results were equel.
I doubt Benq or OEM seller will ever accept warranty claims when you have changed firmware from OEM to Benq.