Being able to pay out individual projects, or specific amounts, rather than everything at once would greatly benefit both the buyer and the seller.

Let's take a hypothetical seller who takes on 15 projects at once.  They are certain they can get them all finished, but it will take about two months.  Our seller is placed in a position where good business practise and paying bills are at odds with one another.  Their choices are to leave all of the money with Commissio until all 15 projects are done, or cash it all out at once.

Now, our seller's rent is due, so they cash out.  But they've had to cash out everything at once.  A week later, slot #12 on their queue is upset that they're taking too long and wants a refund.  The money may have already been spent on bills, or they may have to shuffle money around between accounts if the seller is in a position to have a separate account for commission money.  Either way, it would have just been easier of slot #12's money was never withdrawn from Commissio in the first place.

This would also be helpful for large-ticket sellers.  Buyers could cash out what they need for materials, but leave the rest with Commissio.  This way, fur and padding can be purchased, but the rest of the fursuit money can stay in a somewhat untouchable position in case a refund needs to be issued.

Sellers who do use individual bank accounts for this exact purpose can still cash out in whole if they still chose to, but having the option to not have to would ultimately be easier for everyone.