They could also simply be quoting the distance on the card (160) but getting 152 when they zap it with a rangefinder - as the pin is 8yds forward of centre. Allowance for wind etc. is often rated in terms of 'clubs' eg half, 1 2 etc.
I'd never thought about it before but I guess the explanation that its, the difference (if any) between the measured 'plate' on the teeing area and where the tee markers are on any given day, seems the most sensible
i.e what is the actual length of the hole that day compared to the measured course distance
Its not really a phrase I hear PP's using, just the telly folk