[Gavin Collingwood]

I think you're missing a obvious point here,
There are three manufacturers that run a forward motor car
Schumacher,
Xray,
And Team C.
Of these manufacturers Schumacher have the highest number of top class drivers with the five in that A final being Bloomfield, mossy, McKee, cockrell and Nathan waters (all drivers are regular national A finalist anyway)
Xray only have stu wood (who's not doing nationals this year) and Ian mellish whereas Team C only really have Kev Lee as their "top class" driver
So when you look at it like that when the track and weather suits these forward motor cars, it's not that the KF is the difference, it's the fact Schumacher have a good forward motor car (along with team C and xray) and a big team full of top drivers.
You could say the weather at the nationals has been freakishly dry and warm so far and if they would've been wet/low grip you may have seen these forward motor cars suffer but that's the luck of the draw and they have benefitted.