*Need Help** Comparing the movements between two custom dates

I want to compare the count movements between 2 custom dates.

I am able to get the result if I fix the comparison between selected month and previous month by inserting a calculated column which gets me the previous month, and then then creating a key and performing a lookupvalue to get the previous status. Something like this. 

But I am tired to searching and thinking of alternatives when I am trying to keep the comparator Month as custom. Need help in this