Multi Currency Credit Note Issue

Hi I have an issue here while using Multi Currency - I really need help as I cant proceed further if I can’t resolve this issue - If anyone can help would be great

I have attached the screenshot which has the values - I have an invoice created for the U.P values, however, there is payment which I need to deduct

In this example
Product 1 U.P. (Currency) = 3671.00
Product 2 U.P. (Currency) = 529.00
Total (Currency) = 4200.00

Customer requested for refund
Cancellation Fee = 1200
Product 1 U.P. (Currency) = -3671.00
Product 2 U.P. (Currency) = -529.00
Cancellation FEE: 1200
Total (Currency) = 3200.00

Everything works good, however, the U.P. (Net) still show a negative value adding which is negating the over all calculation

I have checked the forum threads cant find this solution

Please help