I believe mid range was the issue kind of like the wiper arm is soft or the windings ore worn, I used to rebuild those things on the c-130 oil level gauges, really delicate stuff and easy to f up.
If you want accurate, get a sending unit from Europe.
We worked on a diesel powered Jeeps for Europe and the fuel gauge requirements are more strict there. The gauge needs to drop as the level goes down, not stay on Full for like 100 miles and then start to drop, so they had a special sending unit that was more accurate (and more $$$) than the US versions did... They had to read accurately at the ends of the gauge as well as in the middle...