Minibox channels

I'd like to understand better how certain channels get through and certain ones don't. For instance, I receive Esquire on my full-service boxes. Esquire is a digital channel that I receive on both channel 181 and 1181 (HD). With the mini-box, I do get more channels than I did when going coax to tv, but some that you would think would be present aren't. 

How does Cox (or the algorithm) determine which channels get thru. I attempted to get this answer via CHAT SUPPORT, but all I got was "not all channels are available"...duh LOL