Not this old chestnut again!
Consider this.
If I make two identical curries and then mix them together in a single pan does the new double sized curry become magically ovespiced? Of course it doesn't, it'll tatse exactly the same as a single portion and yet there can be no disputing that there is exactly twice as much spice in it as in a single portion.
And, to take this crackpot theory to its logical conclusion, if I make, for example, a pot of curry that is about a hundred times the recipe volume of a single curry I wouldn't have to use any spices at all (well maybe a few grains!).
If you believe that increasing the recipe volume increases the potency of spices the answer is simple; you've changed the cooking method, whether you know it or not.
Madness.