Last Month Sales Formula

I'm using a live query so I can't use the SELECTEDVALUE() function.

I'm trying to create a last 3 month sales measures.  I'm sure there's a more concise way to do this, but my thoughts are to create a last month sales measure, a 2 months ago sales measure, and a 3 months ago sales measure and then sum those measures together. 

Here's my measure for last month, however I believe this is summing last months sales for each year as the total is much higher than it should be.  

Last Month Invoice Qty = CALCULATE(
	SUM(FactSalesOrderDetail[InvoiceQuantity]),
	FILTER(ALL(ActualDeliveryDate),
		ActualDeliveryDate[FiscalMonthNumber] = max(ActualDeliveryDate[FiscalMonthNumber]) - 1
		)
		)

Basically, the above measure is probably summing last months sales for the whole year.  I need it so sum last months sales for this year only.

Thanks in advance