However, there’s one campaign manager I noticed who doesn’t allow that, and that’s Hhampuz. Based on my observation, if the opening is for a Sr. Member, he will only hire a Sr. Member, even if a higher-ranked member applies and agrees to a lower rate.
The OP is not talking about giving lower rank slots to higher ranked members. He is only talking about the reason higher member pay is more than lower members.
I was trying to understand his statement, but maybe I missed the main point.
Still, I’m sure it’s related to the signature campaign. If the question was just about that, then it’s easy to answer, it’s just the signature space size.
However, I wanted to explain everything related to it based on my knowledge and observations.
So I guess my answer not only covers what the OP asked but also adds extra information that's still connected to the topic.