Actually all you need is the active control channel; the reason you put any other frequencies is in case the CC changes, your radio will go to the new one automatically. Just putting them in and making sure they are set for Motorola (both frequency and bank) is all you have to do for 800MHz standard systems. In other words, as long as you are not trying to trunk track a VHF, UHF, 900MHz or 800MHz Splinter systems, that is all you have to do. If you are attempting to trunktrack any of the systems mentioned in the previous sentence, you still have set what ever parameters or band-plan, tables, etc. necessary for that system on which ever radio you are using.
Just for the record, the Pro-95 and the Pro-96 only do control channel trunk tracking on Motorola systems. Any other frequency entered in the bank is basically ignored (unless of course it is conventional). Of the GRE/Radio Shack Trunking scanners, only the Pro-92/2067 requires that all the frequencies of a Motorola system be entered.