You do it by forgetting that both currencies have the same names.
You sell in loonies.
You pay fees in bucks.
Different things entirely.
Among other currencies that use the term 'dollar', Australia, Belize, Brunei, Hong Kong, Jamaica, Namibia, New Zealand, Singapore, Suriname, Taiwan.
If you sold in Hong Kong dollars you'd still be taking in the same amount of money.
If you paid in Singapore dollars you'd still be paying out the same amount of money.