That takes a lot of nerve to bump the trim up at 98 mph when the nose lays down.............more nerve than I have! I always felt when the nose dropped that the prop was no longer carrying the boat well as a result of too much trim or too much overall motor height. I'm not saying you're wrong, but it's interesting to me that works.
Yeah if mine starts trying to drop or not wanting to raise right I'm usually over trimming it, one bump down and it usually drops some r's picks the nose up and jumps up some mph.
Usually when I'm coming up with the motor when I feel it jump up is where it wants to be, up higher than that and the nose wants to fall , rpm's go up and mph goes down, but I've got alot of weight in the nose too.
Troller, graph, rods, plano's , assorted tackle and other items, spare clohes, towels ,rain gear etc.