It's not the retreads. If the tire is run low it will do that new tire or retread. Those failures are at the sidewall where it meets the tread. Retread or new it makes no difference. The problem is that with a tire next to it holding it up in most cases on the trailer the driver has no idea...
That's what I use as well. I have 2 of them. One for each truck.
Note that the weight changes when you move the vehicle a little most of the time. So I move ahead a few feet and recheck. It normally increases but not always.