I don't know about correcting, but easy enough to test. My sloppy editing made my response not so clear, but Van's tested the 2nd one they sent me before putting it in the mail. I double checked it and it prior to installation worked as it should on install. I'd guess if one were to call in the order and request that they test, they probably would.

Anyway, on the bench with a multi-meter on the 100 ohm setting, alligator clip one lead to the terminal and one lead to the "bulkhead". With the arm all the way up (furthest from the pickup) you should have ~10ohms (+/- 1ohm, per fsm). Move the arm down watching for a roughly linear increase and when the arm is all the way down, you should see ~73ohms (+/- 12ohms, per fsm). In the car, you could probably pull the filler tube and move the float arm up with something and do the check. I didn't try that, but I did go in through the filler hole (Barracuda) with a grabber to get the sock from the original pickup out of the tank. I did move the float in trying to nab the sock.

The float arm may need some tweaking to indicate correctly, though the one I finally got that worked that I got was spot on. I did, however tweak it to show empty with 3 gallons in the tank instead of two just to be sure the the pickup would stay covered while cornering with low fuel. This had the net effect of having the 1st 5/8 tank drop rather more quickly than the rest of the tank.

I did try tweaking the arms on the 1st two units I got, but best I could get was either never full, or never empty as it only worked on maybe half of the arm travel.

The 3/8" pickups are dicey to R&R in the car (though the Vans one was far easier than the other two, they are built slightly differently), I imagine a 1/2" pickup would have to be done with the tank at least lowered. The combined diameter of the pickup tube and float are a bit larger than the opening so some maneuvering has to be done to get it in. 5/16" pickup was a cinch to remove in the car.