The comment above is correct, but there may also be adjustments for refunds or chargebacks for transactions that occur after we’ve paid out for the initial transaction, since we would have overpaid. You can learn about all the adjustments here: https://itch.io/docs/creators/payments#account-adjustments
As for minimizing adjustment fees for payout payments: For PayPal payouts, they have a cap on the transaction fee. So if you space your payouts out such that you collect enough to hit that cap then you can avoid fees from requesting those earnings on subsequent payouts.
For PayPal specifically, last I checked they charge up to 25 cents for US based transactions, but 2% of the payout amount up to 25 dollars for international transfers. You can see the most up-to-date fee info on this page: https://www.paypal.com/us/brc/article/paypal-mass-payments
Hope that helps