Try running this and see what you think. I'm not surprised that you had trouble coding it. There must be a better way than what I've come up with.

Well done on taking the time to post all of your set-up scripts ... this is a great start.
But I am having trouble understanding what is so special about...

An iTVF may do what you need.

Like this, perhaps?

DECLARE @actvt_dt DATE = '20150815';

SELECT CASE
    WHEN @actvt_dt BETWEEN '20150814' AND '20150910' THEN
     DATEDIFF(DAY, '20150814', @actvt_dt) + 1
   END;

Another option which may be less painless than comparing scripts is to create two identical temp tables and perform the inserts to them, one from script 1 and one from...