Replying to Ski Measurement Method by Brand

I would be interested in knowing which ski brands measure their skis with a :

post-pressing tip-to-tail length (ON3P)
VS
pre-pressing flat base length (Atomic)

In other words, I mesure my 176 ON3P Kartel from tip to tail, and it's 176 cm.
But when I mesure my 185 Atomic Bent Chetler from tip-to-tail, I get 182.5 cm

What about the other brands?
It's a pretty useful info when buying a new pair of skis.. without trying them..