Hi Tony,
I believe you’re right. For the time being, we’re calculating the shipping class cost for each different item. I believe the issue you’re reporting wouldn’t apply to the “Percent cost”, right? As its calculation depends on the product total.
But for the “Fixed cost”, I think it makes sense. I’ll create a new option for it then, where it’s going to be possible to calculate it for each product or each shipping class.
Let me know your thoughts.