Best to use an inch-lbs torque wrench.
For reference 60 inch lbs = 5ft lbs or 6.7791 nm.
However, as Andy has said, the bolts have to be tightened down following a specific sequence.
If you require this sequence, then let me know.
Here you go.
Lubricate all the linkages and make sure that the micro switches are good.
Does it close with a little bit of manual help?
Also engine has to be running and your battery in good condition.
Is this a current code or an archived code?
Best to clear all codes, just to be sure.
If DTC U1001 reappears, you will have to get a CAN system test performed to identify which control unit is causing the problem.
I have all the control units in stock relating to this issue.
I think that the later cars don't have the wire and the TPMS tool has to be used.
The quote that you have is reasonable providing they guarantee a fix.