Either there is a double fee or the Hotwallet needs to be marked as 0%, however if marked as 0% fee then buying on a cex at 0% fee and withdrawing is also fee free:
Hotwallet -> Holder
To solve this also want a 0% that only works on receive and the hotwallet can be marked as this one sided fee free.
This then also works with a cex cold storage as you'd have both the Hotwallet and ColdWallet marked as receive fee free:
Consider a deposit to cex:
Holder -fee-> Deposit Address -fee-> Hotwallet
Either there is a double fee or the Hotwallet needs to be marked as 0%, however if marked as 0% fee then buying on a cex at 0% fee and withdrawing is also fee free:
Hotwallet -> Holder
To solve this also want a 0% that only works on receive and the hotwallet can be marked as this one sided fee free.
This then also works with a cex cold storage as you'd have both the Hotwallet and ColdWallet marked as receive fee free:
Holder -fee-> Deposit Address -> Hotwallet -> Coldwallet -> Hotwallet -fee-> Holder