Fuel sending unit results..what to do?

73 is empty, 23 is half, half of that span is 25. 73 minus 25 equals 48. Guess what 48 is not 1/4 tank. 1/4 tank is closer to 34. Running out while the gauge shows 1/4 ? Stranger things have happened but I would bet against it. To see empty while you still have a 1/4 or more is much more likely. Your test results show close enough.