Working with Calendar Table and Expiration Dates For Totals

[stevie_westside]

To set this up in a basic way, I have:

Your basic Calendar Table:
Order Table with: Order Number & Expiration Date (along with many other index columns for relationships with other dim tables)

The Table Relationship is Calendar[Date] = Orders[ShipDate]

I am having trouble creating:
Install Base:  The number of Active Warranties on any given date (warranty is active once the product is shipped).
Expired Warranties:  The number of Expired Warranties on any given date

I think the Install Base would be the [running total of shipments] - [running total of expired warranties]

I cannot come up with a caluclation/expression that works. I don't know why I'm having such an issue with this.  Any help from the experts would be very much appreciated.

[stevie_westside]

It matches all my manual arithmetic !  Thank you so much!  Much obliged.

[stevie_westside]

PBIX 

[amitchandak · Accepted solution]

@stevie_westside , Refer to the attached file after signature