Fuel level sensor replacement on 1999 Mercedes-Benz CLK430

I'm getting a guote for about $950 to replace fuel level sensors due to erratic fuel readings. Sounds like mostly labor cost due to tank removal etc. Would that be true, does fuel tank need to be emptied and removed to perform this task.

Asked by for the 1999 Mercedes-Benz CLK430
Hello Try running a can of Chevron Techron as they claim " Additionally, use of Techron concentrate Plus can help protect your fuel gauge from malfunctioning, It has been shown that the active ingredients in Techron Concentrate Plus can prevent harmful sulfur components in gasoline from attacking sensitive electronic fuel sending units on some vehicles. This protection has been shown to last thousands of miles"
And the sending unit is located in the gas tank so it does have to be removed to repair this but I would try the Techron a couple of times first