Can I keep track of how much money each of my sub agents owes me, or do I have to keep that on paper?

Yes, the software keeps a running account for every sub agent you sign up, so you do not have to keep it on paper. Each agent has their own wallet inside the portal. When you receive money from them you credit their account, and when they issue a booking the cost comes out of that balance automatically. The agent sees their own balance and statement when they log in, and you see all of your agents together from the admin side.

You can also set a limit for each agent, so one is allowed to book only against money they have already paid you, while another one you trust can keep booking and settle later. If an agent runs out of balance, the portal stops them at the payment step instead of letting the booking go through, which saves you chasing the money afterwards. Refunds and cancellation charges pass back through the same account, so the balance stays correct on its own.

What does not always happen by itself is matching up money that lands in your bank. When an agent transfers you money, somebody on your side usually has to confirm it before the balance goes up, unless your payment gateway is connected in a way that records the top up for you, and that depends on the gateway and on your plan. Your tax filing and your year end books still belong in accounting software, although you can normally export the agent statements and pass them to your accountant.

Before you open your portal to sub agents, decide which of them you are comfortable letting settle later and which ones should pay you first, and set those limits on their accounts from day one.