Multi currency results in customer accounts having "credits"

Hello, I use multi currency with USD as base currency and SEK and BHT as additional currencies.

I have an e-commerce store which is one customer in manager.io

I record all sales in USD. However, when receiving payment for an invoice, they sometimes go to a BHT bank account.

I use Google to estimate the exchange rate and then issue a bill (separately from manager.io) to customers. I then make a note of the amount I received in BHT.

When completing the transaction in manager.io and specifying that the amount that went to the BHT account, manager.io starts recording “Amount credited” to subsequent customer invoices. I presume this is because it uses a different exchange rate and considers the payments as being overpaid.

How can I force manager to accept the payments I enter as correct and not apply credits to the customer account?

EDIT: Here are some issues that result from this!

Overpayment - Sales Invoice #3
Automatic payment using available credit - Sales Invoice #2

I know I can change the global exchange rates but they always differ from invoice to invoice. I need each invoice exchange rate to be treated as true, instead of going off a global rate which in this case isn’t correct.

PROBLEM SOLVED: When receiving payment in foreign currency, enter the amount your received and THEN simply enter the corresponding (optional) dollar value (in this case the dollar value of the original bill). Everything checks out now in the sales invoice department and no more credits are being recorded.

Perhaps you should set up one customer based on each currency so when you receive funds into the BHT bank you can then issue BHT bill from within Manager. This would eliminate the need for Google exchange rate and the problem with customer applied credits.

You should only use exchange rates if the transactions actually starts within one currency and end up in another currency - The bank taking local currency to pay a foreign currency invoice.

Don’t use exchange rates to create an artificial transaction - where no actual currency transfer occurs

Problem was fixed by entering the original (optional) dollar value when receiving money to the foreign bank. Now however I have a Foreign exchange gains (losses) on the income statement…