Valve Stem Replacement cost $185.00

[H3 Hummer]

I went offroading and aired down my tires and when done I aired them back up with my electric air pump. It is the type that you screw onto you valve stem and plug into the cigarette lighter. Anywho, when taking it off it I stripped the threads on the valve stem and messed it up. It messed it up so I couldn't put more air in it because it would just deflate instead of inflate.
I took it in to get fixed along with some other things. The service writer quoted me $25.00 (which I thought was high) but later called me back to tell me it would be $185.00. The reason being would be due to a new "low tire sensor" replacement $67.00 labor and of course the valve stem. They essentially have to rebuild the tire he said.

So does this seem correct? Another question, does the spare tire have this sensor?