UKHellBob - This is the complete sketch. I have the other that I used to test with the TFT display, but this is the full sketch to test singling out individual digits. If I can figure out the problem here, there that should lead me down the path to figure out the other one.
As for comparing the float values, I'm not understanding what you are getting at. My first value (VOLTS) is a float, and needs to be. Then PresentVolts, which is a static float, but that's as best I understood from post 4 what I needed to do. Everything else is an integer, and I'm not displaying any of them as a float.
EDIT: I am displaying the original value as a float, but that shouldn't be the issue. I might be wrong, but it seems more that the sketch is not breaking down the numbers.