Looks like on Feb 8th they updated their withdrawal fees, and you are correct… it is $20 to withdrawal, that is disappointing, especially since it is a pUSDT withdrawal. They use to have pUSDT and USDT separately, but looks like they have combined them now.
I guess the real cost benefit is getting coins out of Incognito to MyConstant now, you can send them pUSDT directly, which makes your transfer fee almost 0, and once you have stablecoins in MyConstant, they are treated as fiat… so you can withdrawal cash directly without having to unshield, or pay that unshield fee.
You can also reach out on their telegram and talk directly with Andy (https://t.me/andy_9210), he should be able to help you with any specific concerns you may have (as they do update policies frequently).