Subtotal & sumif

Good Morning!

I am using the following formula;

=-SUMIFS(Amount,AccNumber,"400000",Narrative,A5)+-SUMIFS(Amount,AccNumber,"400010",Narrative,A5)+-SUMIFS(Amount,AccNumber,"400020",Narrative,A5)

The raw data however is a table with a slicer in that I would filter depending on the month. I only want the formula to return the visible data for that month so figured this could be done with a SUBTOTAL - however I'm struggling to get this to work?

Is anyone able to help based on the information I have supplied? Please let me know if you need anything further, it's urgent I get this fixed and I'm really struggling!

Many thanks in advance
Laura