The only way you can fully reset your UEFI/BIOS settings is to do it manually from within the BIOS itself, or to remove the battery. Nothing else you run, or do, is going to reset your BIOS settings unless you flash a new BIOS version. So you should not have any problems IF it disables the fast boot for a single restart. As mentioned, the restart to UEFI program version has NOTHING at all to do with the actual UEFI/BIOS version. It is not going to change your BIOS version to an earlier version.
Personally, I'd just reset the BIOS by removing the CMOS battery for five minutes with the power unplugged from the wall, and then go into the BIOS and reconfigure all my custom settings and LEAVE the ultra fast boot setting OFF until such time as you are 100% sure you are happy with the settings, and THEN enable UFB when you are sure you don't have a need to get back in there anytime soon. Or, just leave it on regular fast boot. It's only about a second or two different anyhow and you should have no issues getting into there later with regular fast boot enabled.