API Refunds resulting in not matching total

Hi,

I am creating orders via API and recently started doing refunds as well. I am specifying the item in the refund, which results in Shopify adjusting the Order tax total. Thats is good, however, the way its displayed is confusing and I am trying to make sense of it.

In the added image, the taxes were first 7.99 and a total paid amount of 110.98. After refunding one item the tax was reduced by 3.10 (as I expected) to 4.89 and it shows that now the order total is 67.88 which is correct. However, the Net Payment presented is as if the shopper had paid 70.98 and not 67.88. Why is that if the total refunded amount was 40 (item total) + 3.10 (item tax)?

Thanks!!