Greentext

Logically it's just fluid dynamics. If you dive into a pool, you'll go deeper quicker than if you belly flop. You can't really swim in air, but it's the same principle. No I don't have the math, you'd need a wind tunnel to measure each of the actual coefficients of drag, but something as simple as hand position could have a big impact on drag, which impacts both the acceleration and the terminal velocity.

So what I'm picturing is diving (like a swim dive) off the building, then rolling into a horizontal position after some time with the higher acceleration. It should at least lower the expected height you'd need to jump from to reach the horizontal terminal velocity.

That said, the height to reach diving terminal velocity would be even higher than your first number (unless the drag coefficient you used was actually for the vertical position).

Get a wing suit and the difference between a dive and glide is even more extreme (to the point where terminal velocity might need to be described as lift instead).

I leaned on https://discover.hubpages.com/education/Drag-Force-and-the-Terminal-Velocity-of-a-Human
and specifically:
https://images.saymedia-content.com/.image/c_limit%2Ccs_srgb%2Cq_auto:eco%2Cw_700/MTg2OTk1MDI4MDg4ODU4NTA4/drag-force-and-the-terminal-velocity-of-a-human.webp
I estimated the area of a body in vertical position as 1/4 of a body in horizontal position.
With C going from 1 to 0.7 and A going from whatever to 1/4 of that, this results in a terminal velocity increase of over factor 2.