balance shaft installation

my mobile mechanic is replacing my water pump and encountered a broken balance shaft belt. He's says he can get a new one back on, but has never replaced one before. Should I let him continue in order to avoid another mechanic breaking down the timing belt cover again? Or should I just let him fix the water pump? Also, is changing the balance shaft belt part of the timing belt change? If so, my previous auto shop did not replace this belt in 2002 when I had my timing belt change done.
Desperately need some suggestions :confused:

I did my TB a month or two ago at 60,000 miles. I got three quotes, and all of them quoted both belts.

If either one breaks or slips teeth, you are well and truly screwed, so, yes, do 'em both.

As with the timing belt, alignment of the cogs is important. All the manuals and computer programs (used by service guys) show how to do this.

Peter