Need help with measure

Here is a sample file:

https://drive.google.com/file/d/1yjp20i4tZP0GAnSbSe-06f4TtkQowIrh/view?usp=sharing 

There is two sheets, and the results in each sheet is correct, but for the result in the sheet 'Forecast' to be correct, I need to create a new date dimension as described above. I would like to use just the Primary date dimension.

Hope this gives You what You need.

Thx in advance 🙂