If it's blowby though, isn't the only way that oil could get back up into the intake is if it went through the PCV system? No excess pressure at the oil filler cap would seem to indicate that it's not blowby, although if it was only checked at idle the higher rpm condition described wouldn't have been addressed.

For whatever reason, the PCV systems on individual VX's seem to just be hit or miss as to whether they function correctly. A simple breather filter to replace the PCV valve eliminates even the chance of what's being described as happening though.

If a VX suffers from oil usage because of a problem with the piston rings, oil usage is going to occur anyway, regardless of whether a PCV system is even in place.