You can go direct. BIOS flashing does not require any sort of incremental steps. Only thing you need to be aware of is that my mod is actually using the Asus SLIC (thanks for reminding me to edit that!) which may or may not be different from the one in your existing BIOS mod. It is just a simple matter of putting the matching Asus XRM-MS file to your existing OS install to re-activate it if need be.
Thanks a lot for your quick reply. I am probably going to make the switch to 7 in the next week or so. I'll report back to let you know how it goes. Much appreciated.