How can your rate increase but your total costs decrease?

Processing companies quote a very low fee, say 1.49%. What the processing
companies do not tell you is how much you will be charged for the cards
that do not qualify for this low fee. There will be many cards that do
not qualify for this low fee. The cards that do not qualify for this low
fee will have a surcharge added to the low fee. The surcharge can be 2%
or more on top of the low fee. So now you are paying 3.49%.
The low fee is mostly for debit cards only.
B2B merchants will process less debit cards than a merchant who is selling
to consumers. A B2B fee of 2% and a surcharge of .5% equals a total cost
of 2.5%. This 2.5% total fee is less than 1.39% and a surcharge fee of 2%
which equals 3.39%.
Your “fee” is higher but your total overall cost is lower.