Since im paying if it was me, I would tell them screw the instuction book do what I say as your expecting ME to pay.
I would have simply instructed them too.
Scan it and see the well known fault code.
Compression test it.
Inspect the head using an inspection camera.
Take the upper and lower timing chain covers off and check the timing is aligned or not or jumped one or more teeth.
Check the tensioner resting rachet is keeping the tension.
I would also be asking to speak face to face with the master tech doing the work!
Also supply him with a print out from the american forum of the know issue.