API Token Fees Decreased or Increased ?!

Hi, As you know, OpenAI recently offered another discount on Gpt-4o API usage. BUT, my August usage cost me %25 more than it did in July. Even if I did not count the tokens, I can clearly see from my other statistics that my usage is almost identical. Does anybody else have a similar experience? Why have my costs increased not to mention decreasing?

Update:
Look at my ss. There are two different GPT4o model used at the same days until the end of the month. This is simply not possible because I only have 1 active assistant in this project. Incredible. Any idea?