Comparing two dates using one calendar table and USERELATIONSHIP

Hi All, 

I want to compare two dates in a single measure to return a count of where delivery date > estimated delivery date within a period.

I have two tables:

1) Fact Sales ([Order ID], [Est Delivery Date ID], [Delivery Date ID])

2) Dim Date ([D Date ID], [D Date])

I can return a counts of [est delivery date] and [delivery date] each day/month/year using:

Count of estimated:CALCULATE(COUNTA([ORDER ID]),USERELATIONSHIP([EST DELIVERY DATE ID], [D DATE ID])

Count of deliveries:CALCULATE(COUNTA([ORDER ID]),USERELATIONSHIP([DELIVERY DATE ID], [D DATE ID])

However I want to now compare the two date fileds to return a count of late deliveries (EDD > DD). If I used two separate date dimensions for EDD and DD I could just use similar to:

SUMX('FACT SALES',IF( RELATED(DD_DIMENSION[DATE]) >RELATED(EDD_DIMENSION[DATE]),1,0))

How can I replicate this formula using USERELATIONSHIP?

In SQL Terms this would be equal to:

Select 

Period,

Sum(Case when EDD>DD then 1 else 0 end)

From

Table

Group by

Period

Thanks!

Pbix