Alignment Question

I watched a shop align my RCI American Spirit last week, and he did an adjustment that I didn't see in the service manual. He did check the 10.240 crystal and set that correctly, and then he adjusted something he called the "time-base" until his frequency counter said exactly .455 hz. Im sure it was probably in the IF section, but I don't know what pot and test point he used. Im sure this wasn't in the service manual either. Any idea what he adjusted?