Doesn't seem unusual to me at all. At around 2500 rpms is about where
mine drops off plane and essentiallly plows water....

Ok, let's say your boat drops off plane at 2500 RPM. (Are we talking OB motor?)

Let's say that just off plane in your boat is
9 mph.

At 2600 rpm we'll say you're back on plane at 10-11 mph. Adding 400 rpm to that
will bring you to 25 mph?

Something is fracturing my paradigm. Very light boats, outboard motors, or
something else I don't typically experience.