Payouts - negative and positive adjustments

[LuisaV]

Helllo

I have a question regarding adjustments on the Payouts page. On one day we have a positive adjustment of 11.98 EUR which is due to fees Shopify paid back to us because we refunded money to customers. At least as far as I know, I hope that knowledge is correct.

Yet there are a lot of days with negative adjustments, varying between -10 EUR and -650 EUR. One of the Support people already sent me this Help Doc https://help.shopify.com/en/manual/shipping/shopify-shipping/billing-and-taxes#price-adjustments but that doesn't help in my case because our carrier doesn't have a Shopify access and therefore no one can say whether the shipping costs, product weight etc. was correct or incorrect (most of the time shipping is free anyway). It's also curious that the top of the payout page says "-650 EUR adjustment" (and conducts that amount from our payout) while the detail view (every individual order) only shows positive adjustments due to refunds. So there's no way for me to retrace why -650 EUR exists. 

An explanation is much appreciated.

Best regards

Luisa