I also think the comment about keeping two men pleased is nonsense. I don't do MMF but I do MFF and I enjoy this partly because of the visual stimulus, this is pretty common for most men. I don't find that I work twice as hard to keep both girls entertained and I don't make that comment as a boast, I really don't think anyone does.
In a 1-2-1 booking I only have one cock in one place at a time. The MMFs I have done have consisted of two cocks being one each end at all times which is much harder work than the most energetic 1-2-1.
I don't state you are paying for my time as that is just for a disclaimer in countries where it is illegal and we all know that. I charge by time slots for the services you want. If it was just for my time I would not bother doing anything in the booking as you would still get my time without sex.
I charge double for two men as it is much harder than two women as entertaining two women you don't have two cocks ramming into you at both ends non stop. If two women booked me I would not charge double as even full on it is not exhausting unlike two men. You may like the visual side and stop to hv a look but not all men do and some want to spend the whole time banging at both ends. It is really hard work and much more physically demanding than any 1-2-1. You also have to be constantly on guard. More so than in a 1-2-1.
If it was two clients I knew and trusted then it wouldn't be double the price however this is never the case and it is normally young lads who I don't know or trust which is why I rarely agree to do them anymore