We are talking about GMRS, and there are only 8 Repeater Channels but they can have whatever number/name you want to call them. They are generally referred to as Repeater Channels 1-8 or, or starting after channel 22 - Channels 23-30, or labeled as their shared simplex channel names "Repeater 15 - 22"..
..and in the GMRS world we never need to use the term "offset".. On a GMRS radio one does not have to think or care about the "offset".. This term is usually only used by "some people", for unknown reasons .... actually we know the reasons, but I am far too nice to repeat them here.