Calculated measure doesn't total

Hi. Need a hand please.

Here is a sample workbook: https://we.tl/t-tVdRmLibUe

I have a measure called SDayLM Sales, which gives me a value from a special date table that aligns same day of the month to last month within the same week (ex. 1st Monday of this month to 1st Monday of last month etc). 

My question is, how can I get the SDayLM Sales field to show a total in this matrix? It doesn't auto grand total, and I've tried using a TOTALMTD formula but I couldn't get that working either. When you remove the individual dates it doesn't give a total either. How can I accomplish this?

Attached is a workbook as well. Please note, in my real workbook The Invoice Table and Date Table cannot be changed whatsoever - they're part of a Live model. I can only change the relationship etc for the Alignment Table.

Thanks!