This would be true if bosses dropped the same amount of loot in 10 and 25 man. Hint: they don't.
10 kills in 10 man = 20 items = 2 TF which means 20% of the raiders got TF loot
10 kills in 25 man = 60 items = 15 TF which means 60% of the raiders got TF loot
25 man are gearing up on TF three times as fast!