Fuel Sending Unit diagnosis on 2006 Nissan Murano

After overfilling my fuel tank I noticed that the fuel gauge on my 06 Murano only showed about 7/8's of a tank rather than "full". The "Distance to Empty" (DTE) was also showing less than it should have. After driving around for a bit, where presumably the tank physically had less than 7/8's fuel, the fuel gauge and DTE seemed to work OK again.
I've done a bit of research and it looks like there is a problem with the fuel level sender in the tank. My questions are:
1) Why would overfilling the tank cause the fuel level senssor to fail? I find the shut-off at gas stations is often too sensitive, hence I kept filling after the first couple of clicks, oops.
2) Can the sensor be repaired or must it be replaced? I'm on a bit of a budget...
3) There are TWO level sensors in the tank, is there a way to isolate and identify the bad sender? They are too expensive to simply replace both!
I'm a fairly competent DIY'er so plan on tackling this job myself.
TIA for the replies!

Asked by for the 2006 Nissan Murano
Perhaps I can help a bit here, There is no way overfilling your fuel tank should damage your fuel level sensor. A lot of manufactures have been having problems with level sensors the last few years. The failed sensor must be replaced (we are all hoping the new sensors are better than the old ones). I cannot specifically address the two fuel sensors. I would however suspect that there is a fault code stored in the engine control computer related to one or both of the level sensors. It may not be a bad idea to have the engine computer scanned for fault code(s) before replacing any sensors.