App Store App not installing

This is more about expected functionality in my environment I think...
We have users with manually installed Sonicwall Mobile Connect app.
It's showing as needing an update in the App Store.
I added the app to our VPP and to a test machine and in the JSS it shows as "In Use" under "Mac App Store Apps" for that test machine, yet it's not updating.
Do I have to delete the existing app for my managed app to be installed?
I was hoping it would just see the installed app and update it.
Thanks for any assistance.