Maybe because the bulk (90%) of my riding instruction has been with a dressage trainer and in dressage saddles?
Exactly. In fact, if that's the case, why are you posting advice in jumping and forward seat threads? Dressage experience isn't always applicable to forward seat or hunt seat riding.
Also consider that riding to fences in a full seat means that you have to be able to accurately judge your take off, and be prepared to fold into two point at the correct moment. Another advanced skill.
Riding to your fences in two point *greatly* reduces the liklihood that the rider will misjudge, jump ahead or get left behind. You have to log a certain amount of mileage riding fences to gain the confidence and experience to be able to judge distance and develop timing, riding to fences in two point is the way most people gain sufficient experience to do so safely.