I *think* the idea is that you can gain advances without restriction *but* when you do a reequip you are only allowed to recruit new agents to bring you up to 10pp. And you can’t sack anyone except by giving them the Early Retirement skill after they get three major injuries.
So you can go above the limits through advancement, but can’t recruit anyone else. I seem to remember the idea is kinda that you are likely to end up with less, more experienced and traumatised operatives. It’s supposed to be thematic, representing the loniless and isolation of fighting the mythos.
So, assuming that is right if you have 17pp of dudes with 10ep of equipment if you get promoted after 5 wins when you reequip you don’t have to, and indeed can’t, remove any dudes, but you can bring yourself up to 15ep of equipment.
However, if a 5 point agent is then killed, reducing the team to 12pp, you could then do a re-equip and recruit 3 points of operatives to bring you back up to 15 points.