Charging an iSi siphon when adjusting a recipe

It is a Parmesan mousse that I want to foam. The original recipe called for 1 pint with 2 charges of nitrous. I am making 1/2 pint. I just wondered that if you scale a recipe for an iSi siphon up or down, does the amount of nitrous need to be adjusted. I am assuming it does since, say half the volume of liquid would require half the amount of gas to achieve the same consistency.

Yes, that should work in this case, as it is a fairly simple application - but I don't have enough experience with this method to be able to promise you that in all cases (using any liquid ingredient), that half a recipe would always require half the number of cartridges.

By the way, please do report back on how it turns out! ;o)