Normally I would agree gain is gain right.. adding some at one stage just requires less at another stage. But with the gain all the way up on these things the signal is really hot, a pad would be necessary on most mixers to produce any functional range of use on the channel strip that isn't over driving everything, so there is really no need for it to be set that high.
Strangely in this series the body pack has an output trim control but the handheld does not.. it's output level is fixed so it can't overload the receiver. Makes it easier to use I guess.
At a church I was doing some service call work had a couple Freeport body packs and those did need the gain adjusted on the pack. The handheld was fine so I never opened it up to look for a gain control. I did not notice anything crazy as for the output level into their small Soundcraft board when I turned the receivers up. I set the levels full up to prevent little fingers from turning them up since they had the receivers setting out in the wide open on shelf in their sound booth.
