Inaccurate price rounding at the checkout

Shopify Plus
1

Perhaps anybody has solved this scenario:

  1. Normal product price: 13.80 EUR
  2. We have a discount script written with Script Editor, that provides discount for logged in users (sort of member-only pricing). We set discount for this product to 49%. the price after 49% discount is 7.038, we round it and show 7.04 for the customer at all checkout steps.
  3. However the customer is then charged 70.38 if he buys 10 of the same item for example. Shopify is taking a price of 7.038 and not the price we provide for the customer

So we end-up either overcharging or undercharging the customer if they buy more than 1 of the same item. It’s by cents, but it creates a mess in our accounting system and we need to do returns of 4 cents where transaction costs 30 cents.

Shopify Plus support hasn’t been helpful yet, they keep referring to the limitation in Script Editor, but that doesn’t solve the problem.

Anyone with a similar issue?