Hi Sean, couldn't agree more.

Vosa have recommended running the rollers together (to speed up the testing process?) to get a figure which locks the rollers out at the lowest figure (as Aidan said). This usually gives a good and equal reading.
i.e. rollers lock on n/s/f at 300kg the o/s/f reading is 300~ too.

I can see this could be a problem if you're using older rollers that don't both turn off when run together once one locks out.

The special notice then says (iirc) if the vehicle fails to meet the minimum efficiency then run the rollers individually. (How do you know the efficiency is too low whilst carrying out the test, unless you work it out, have a super duper roller setup or log back onto the Vosa computer to enter the figures)!
Which then negates the time saved from running the rollers together!

VOSA - a**e and elbow as usual?!