The cap comes from terminal velocity. Unless the fall happens in a vacuum, you shouldn't ignore it. (Or if launched into the ground / at a wall at higher than terminal velocity).
If you fell while tied to a giant rock, your terminal velocity would be significantly higher, because rocks are denser than people (i.e. water). Drag is approximately proportional to area, but weight is proportional to volume.
Even a large amount of people tied together could have a higher terminal velocity. From a high fall, a mouse walks away, a cat might survive with broken bones, a human dies, a horse splashes.
If we're only talking about extreme height on a single human, there's no way you'll hit the ground faster than terminal velocity.
A human-size/shape/density object falling even from outside the atmosphere (on Earth) still slows down to terminal velocity before it reaches the ground. High in the troposphere isn't even high enough to char the outside from picking up speed in thin air high up. (related: can you cook a steak by dropping it? https://what-if.xkcd.com/28/ mentions human skydiving from great height (Felix Baumgartner)).
Using that spell, the victim would overshoot the reversed-gravity zone a bit, because they'd be moving upward (at <= terminal velocity) when they leave the area of effect. That's good for a significant amount of extra height, since the air is significantly thinner at 11 miles up so terminal velocity is high. But that doesn't lead to higher impact velocity after falling all the way to the bottom of the troposphere.