PRV - What happens when it fails?

111 psi from mains.
WILKINS MODEL 70 (25-75 range)

The pressure after the PRV is also 111psi. No matter how I adjust the PRV it's still 111psi. Aside from this, at .96 GPM, the pressure drops down to 40psi. (a drop of 71psi) So at a minimal flow - it's killing my water pressure; and at zero flow, it's letting 111psi through.

Is this what happens when a PRV goes bad? Any ideas appreciated...
I saw some rebuild kits online.. or should I just buy a new valve?

If you can buy the rebuild kit, why not?
That would fix it.

Most plumbers replace, because they are there at the job.
and leaving to find a rebuild kit online, and then waiting for it, and then rescheduling it, that's a lot of "ifs" and a lot of time spent.
It's easier for us, and about the same for the homeowner to just pop a new valve in.