The rules for coalescing are actually a little more complicated.

Transactions are coalesced when they are older than the oldest .client file.
Each time a client checks in, it deletes all of its client files older than an hour except 1.

So if I sync my work machine at 5 pm before leaving work, and again at 8 am the next morning, the 5 pm client file will be kept, and a new one added at 8 am. No matter how often I sync after that, the 5 pm .client file will be kept until the 8 am .client file becomes an hour old. So if I sync again at 9:01 am, the 5 pm .client file will be deleted and any changes between 5 pm and the next .client file (maybe 10 pm from my iPhone?) will be coalesced. I'm hoping to put together a reference on this for the nerdier among us.

Thanks, Lizard! That is extremely helpful!

-Dennis