[kaptain]

What is the hourly rate? I missed something about what happened to the batteries.

I am not sure about the hourly rate, so sent an email last night to the shop asking for some clarification on how many hours total and what the shop labor rate is, resulting a bill with a labor charge over $9k,  I am waiting for a response. 

[update with an insert, after I got an email response from the shop]

"....our labor rate is $175.00 hr. It is the same rate as the last repair on your RV. That is 55.8 hours that it took us to make this repair, "...

[end of update/insert]

As far as the batteries - that was 3 months ago, upon receiving an email notice saying they have finished repairs and the coach is ready for pickup. 
Once I get to the shop, only found the engine could not be started because the batteries seems dead, the shop then brought a mobile diesel-powered charger, charged for 30 minutes or so, and was able to start the engine. The shop manager commented I have bad batteries and they had to use a charger during most or the entire time of repair/diagnosis. It was a surprise because the batteries in the engine bay were pretty new, dated 03/22!

As soon as I hit on the highway, smelled smoke, and determined the smoke came from the backside of the coach, then I realized I had to stop. Distance is about 3 miles away from the shop.
Then I hopped onto my partner's truck, and went back to the shop for advise. The shop says it needs to be towed back for further diagnosis. That saga was described here in this thread 3 months ago: http://newellgurus.com/showthread.php?tid=6843, at post #6