As per the documentation, yes you are correct. You can of course make profit on the client billing, depending on the budjet of your client. I mean shopify plans are quite similar…
Shopify Basic costs $29 monthly (and 2.9% + 30¢ per transaction). The Shopify plan is $79 monthly (and 2.6% + 30¢ per transaction). Advanced Shopify is $299 monthly (and 2.4% + 30¢ per transaction).