Lowering the top how slow should it go down
 

I have a 1987 25ft Voyager it goes up slow maybe normal and drops down pretty fast I think to fast. ...i watched some videos and compared to them I'm right. I'm wondering if maybe there is a valve stuck open or something. The camper had set with the top up for 2-3years before I bought it.

Hi-Lo claimed the top goes up in 12 seconds and I guess it goes down about the same speed. I have never timed it myself but would I say 12 seconds is pretty close. Your battery condition can affect the speed the pump will run, lowering requires no power other than actuating the solenoid valve to release the fluid back into the reservoir.

Went out and cycled mine, 2003 - 27'er, 14 sec up and 12 sec down. That seems to about the same as all the Hi Los I've owned. I yours is going down faster than that, lets say in about 6 or 8 seconds, then you may have a restrictor gone bad. As Rich said, a solenoid opens to lower, allowing fluid to return to the reservoir. IF there is a restrictor of any kind, I don't know where it's located!
Tree

Added thought, if you have a know good, fully charged battery, perhaps cycling the top several times may "unstick" an open valve. Just a thought. Up a foot or two, then down, a few times. Might work and costs nothing.