I haven't ordered my van yet. Just wondering if the Powered PentHouse can be stopped
half way up. And if so, can it be brought down from that position
or does it have to continue all the way up and then back down?
There may be times when I just need a little stand-up room inside to slip into
my wetsuit and I don't need it all the way up. That's all.

Absolutely. You can go up or down any amount. If you let go of the button it stops.