You missed my point. If the average request uses more tokens than 4.5, then you will pay more sending those requests to 4.6 than 4.5.

Imagine 2 models where when asking a yes or no question the first model just outputs a single yes or no then but the second model outputs a 10 page essay and then either yes or no. They could have the same price per token but ultimately one will be cheaper to ask questions to.