Thanks triadic.
Above 5000 ft I would suggest the Area Frequency. Above the lid of the MULTICOM and below 5000 there is no requirement, but the Area Frequency might be the best choice.
I take it, then, that you support FIA boundaries and frequencies remaining on charts?
The idea is that with the MULTICOM you don't know when you are 'in the vicinity' of any strip etc, so using the MULTICOM is simple.
Exactly the same logic and simplicity applies to using Area, I would have thought. If you can work out the Area frequency to use above 5,000 ...
And you don't have to change from Area to MULTICOM when you descend below the 'lid'.
And whether you're on MULTICOM or Area, you still have to change to the CTAF of aerodromes in the vicinity that don't use 126.7.
I'm still not getting it.