Sounds like a play on terminology to me.
Normally the GA fleet is counted from the VH list, yer?
But if you suddenly decided to count up all private aircraft from the VH and numbers lists, you'd easily double the size of the counted fleet.
About the same adjustment of numbers they use for the unemployed...stick on a course they day the head count is done....they are students, not unemployed!
"we've doubled the private fleet, so we need to double the regulation" he screeched as he chased his goanna dinner through the scrub
Just seems like dodgy accounting.