Ask HN: Shopify 3rd party processor fee.. Questions

Hello. I have a client that wants to use Shopify and also wants to use their current processor.

I can't get a straight answer from support.

Assume Advanced package for pricing. If someone uses a 3rd party processor does shopify apply their flat rate fee on top of the 3rd party fee?

The answer I got from support was yes they do. But this doesn't make sense because the 3rd party gateway would be tied to the processor which would apply their own fees and shopify is simply charging a fee of 0.5% to do that.

Online Canadian credit card rates -"2.4% + 30¢ CAD" ( this is a Flat rate Processing fee that shopify is passing on from their processor on to the store)

"3rd party fees on transactions not processed through Shopify Payments" - 0.5%

I can get my client cost + 0.05% which is still way cheaper with the 0.5% shopify fee.

So would my client be charged 2.4% + 30 cents + 0.5% + (processor cost) + 0.05% ?

If so this would be absurd.

Thank you.