When reviewing Commercial Invoices while having USD as source currency and CAD as target currency, you might realize that:

  • The value in CAD might fluctuate
  • The value in CAD is off up or down by 1 cent CAD

This is a result of a combination of truncation errors and round-off errors (as detailed at Round-off error and Truncation error).

When data is submitted to Canada Post, Canada Post requires to submit data in CAD currency and supply conversion rate, as their documentation indicates below:

Noting so, customs-value-per-unit must be in CAD rounded to 2 digits, and conversion-from-cad contains USD/CAD conversion rate. Canada Post takes the data and converts back from CAD to USD

because it involves the operations of division and multiplication and floating point arithmetic, leading to potential round-off errors.

Also, since currency rates change each hour, the results on the Commercial Invoice could be different each hour due to Canada Post requirements for currency conversion, which happens back and forth when techSHIP :

  • First converts USD to CAD to send over API
  • Then Canada Post converts back from CAD to USD to render the Commercial Invoice

This is an unavoidable issue, representative of the process described below, yet it should not impact operations.