Which currency the tax is in

Tax is assessed in the currency of the transaction. Tax assessed in a currency other than the naira is paid in that currency.

So a dollar sale is a dollar matter for assessment, even though your books also carry the naira value at the rate on the day.

BizBrada keeps both: the original amount in the currency you traded in, and the naira value frozen at the rate you used. Nothing is silently reconverted later.

Your returns are prepared on the frozen naira value, because that is the figure your records, your dashboard and every return you have already filed are built on — moving it later would move a number you have defended. Where a period includes foreign trade, the return also shows what was traded in each currency, and the rate that produced the naira figure, so the currency of assessment is on the face of it.

If the tax authority assesses a dollar transaction in dollars, that assessment is paid in dollars. Show them the currency panel on the return: the same records, in the currency they were traded in.