Confusing Share Site Pricing

Hi everyone,

I just transferred a site to a client and then saw a message that said we had to buy extra seats if i wanted to be given more than read only access.

I encouraged the client to buy one extra seat ($60 USD) thinking this would do the trick. Unfortunately the client was still unable to share full access with me and it said it needed yet another seat?

I dont get it, what was the $60 for?

Thanks in advance for your help