The math:
((Actual non-pending payments * Prolly the money you got per sale after itch 10% share by default & processor fee) * 30% tax since you didn't give itch your TIN ) - Tax Identity Verification
The result:
((25*.38)*.7)-3= 3.65
Couple of cents off, but it looks accurate to me
The default is 10%, if it's showing 40% it is because YOU increased it to 40% at some point while having a brain fart. https://itch.io/docs/creators/payments