I don't really get it to be honest. With the default blizzard interface I have 'actionbar button 1' tied to 1. During combat I can iterate through different states of this actionbar, and the first slot in this bar will always be linked to 1. The same can be done with Bartender.

Are you saying that only a hotkey can page the actionbar, and not by calling it through the any lua code (during combat)? Since bartender seems to use their own set of keybinds I was under the impression that there should be at least a 'call' possible to alter the state.

So lets forget about bartender, there is no way to iterate through the default actionbar(s) by calling it in combat?