Latitude E5530 Alps touchpad two-finger scroll, works very poorly in one direction

On a Dell Latitude E5530 with the Alps touchpad, I find that the two-finger scroll gesture works very poorly in one direction. (I have the "reverse direction" option selected, and I can easily scroll webpages down, but up sometimes works okay, but often scrolls very very little at a time, or I have to press down quite hard on the touchpad to get it to scroll correctly).

I also notice that when I two-finger-tap to get the right-click menu, it often misses it, and I have to do it again, harder. But it doesn't seem that just "harder" is the issue, because two-finger scrolling webpages down always works well; it's just up that works poorly/ requires me to press much harder.

This is under Windows 10 Pro 64-bit; has happened under all Windows 10 versions (Anniversary, Creators Update, and Fall Creators Update), and has the Microsoft-signed, Alps-labelled, version 10.1207.101.103 date 6/23/2015 driver.

I have tried reducing the TouchGuard sensitivity; that didn't help. I've turned off all other gestures just to make sure that the touchpad wasn't misinterpreting my gestures - that also did not help.

Any suggestions?

thanks,
-Jay