2008 Prius ticking 2-1/2 Months Dealer Repair!! Still waiting!!

I am still waiting for my repair for the valve ticking problem repair!!
Car in the dealer since 2nd week January 2013
The dealer took the valve assembly apart and performed ?? work.
Re-assembled and it still made the sound.
The Toyota certified master mechanic, replaced the timing "can looking device"
which drives the timing chain between the two cam shafts.
Still made noise...
They then inquired to Toyota and were told to look for a "nick" in the engine block which would produce a timing issue that in turn caused the ticking.
They ordered a Short Block and are now re-assembling.
Does anybody have some intelligent questions to ask the Master mechanic?
Are they throwing me a curve ball?

 

Yes, thankfully I had paid for an extended "platinum" add-on warranty... I am the second owner.
The dealer loaned a "track"car. 2013 corolla.

 

Yes, they did find something on the block. Under the platinum insurance, it's req,d that the insurance adjuster justify the expense. They examined it and approved the repairs. I told the mechanic to take his time repairing the car, and to return the motor to its former stealth quietness.

 

Here is a photo of the two camshafts and on the lower left is the can like device which advances or retards timing.

 

The Prius has just over 91000 miles. Aside from the deductible, it's paid for. The only thing is.... I've spent an additional $600 bucks extra on the 4200 miles driven in the loaner... Ouch!