I understand all of that. I’ve had an on-line business for over 20 years. I’ve only ever had this issue on the Shopify platform. I have always made money on shipping and with Shopify I loose money with almost every shipment…some I make as much at 80cents.
When I go to print the shipping label - Shopify states what the value of the label is in Canadian $'s and it usually matches the amount the Customer has paid less the $1.50 (or sometimes less even more than that if I use a smaller box). So, that is good. It also usually states the amount I will be charged in US$. If I calculate the exchange rate used at this time - it’s usually about 1.26.
When I get my Bill for Shipping I create a spread sheet starting with downloading the shipping bill into excel. This gives me the Order numbers and Shipping in US $. I then use the PayPal notice and have to calculate the exchange rate (easy enough - but odd since the PayPal Invoice started out in Canadian and gets converted to US - why not leave it in Canadian…yes, I know, Shopify deals only in US $). PayPal uses a very different exchange rate - about 1.3 real world exchange rates don’t fluctuate this dramatically in just a few days - but they do from institution to institution. Which could be the problem.
Bottom line - if I charge my customers $1.50 on every sale -why do I not get that $1.50 when it appears that I will at the moment I purchase the label. There is a problem with how this is managed on Shopify, since I have never had this issue in 20 years prior to using Shopify. AND - in the back end of Shopify where I added the $1.50 it should say “You may not get this money - don’t count on it.” The wording currently indicates that the amount I enter is for packaging and handling.