I can't see where you're located since your profile is set to private, but in my own case, I live in the UK so Upwork deducts a further 20% tax on their 20% fee. This should be clear if you look at your transaction history.
Timofey G wrote:
Hello. I just finished my $75 contract and get paid. If Upwork takes 20% fee then I should get $60 but it's only $57 now pending in my report. There was no bonuses. Just one $75 milestone. Who stole my 3 bucks?
Your government as VAT on the service fee?