How far from warranty were you? Did you notice and reported the ticking sound to BMW within your warranty period?
According to the TSB you posted. you shouldnt be paying any cost...under warrnty Information:
Covered under the terms of the BMW New Vehicle Limited Warranty, or the Certified Pre-Owned program.
maybe try another dealership...or get some quotes from sponsors here, showing them the TSB and then compare the price....
personally, i will get it fix for I will go bonker hearing the ticking sound....thats a mental torture..