it's the same net result. you still have to organise the same amount of stuff.
25 people have to turn up (+ bench) - you still have to set raid assignments
10 people have to turn up (+ bench) - you still have to set raid assignments.
what exactly is there "more to do". i dont see a logical justification of 25mans getting more than a 10man when both are the same "thing" just different. Also if its so much more work don't do it. You knew what you were signing up for. Why should you get more, if thats how you choose to play? Why diminish a 10man's choice when you had the same choice.