The real issue is that ErP didn't work when Doug tried it. It solves all of these BIOS-created problems, by making "power off" mean "99.9% powered-off" again.

I use a very recent GigaByte mobo here with that feature, and my power-on button does still work fine.

Try it again?
Look for BIOS updates that might fix the bug?
RMA the defective mobo?