Correct, but of course at the expense of number of pellet strikes.
Shot size selection requires finding a workable balance for both the game and the range.
The 'style' of shooting must be considered also.
Brits are very fond of their #6 at 270/oz, but that's generally used for high elevation 'driven' shooting. We have a very good simulation of that here and I can attest to the effectiveness of that classic load when the birds show their underside to the gun.
That equates to about a US #7, and I really would hesitate before an up the tailpipe shot at a tough old rooster... unless of course the elusive 'perfect point and flush' could be achieved and the hammer dropped at 25 yards.
