Excel: Taking a value based on specific dates ranges - if statements?

I'm dealing with accounting dates, where the new month may start on 26th for example.

Currently, I have formula set up to pick a exchange rate based on what month a payment was made. So if I paid something on May, excel will get the exchange rate from May.

But I now need it to pick it based on a specific date. So if I made a payment on the 26th of May, but the account month start on the 20th of May, I need it to pick the June currency.

I'm not quite sure how to do this, maybe, two ifs statements <=01/05/18 and >=20/05/18. Or perhaps, create a range of dates in once cell?

Current formula:

=SUMIFS('Exchange Rates'!F9:F1378, table of exchange rates 'Exchange Rates'!B9:B1378,L563, picks up what currency to use EUR or GBP 'Exchange Rates'!D9:D1378,TEXT(J563,"yyyymm")) picks up what date to use