Percent evolution Month over Month

Hello!

I've received a report to complete and add some visuals, and also creating some more measures. I'm trying to calculate the % evolution through month over month. 

The existing graph looks like this, and it's bringing the data correctly:

It uses this measure to complete the lines of the visual:

Rank %MS Brand = 
   IF(SELECTEDVALUE('SDBR StgDeParaMercado'[RB VS CONC]) = "CONC",
    CALCULATE([% Price MS],
    FILTER(ALL('SDBR StgDeParaMercado'[RB VS CONC]),[Rank Brand] <= 5)),
    CALCULATE([% Price MS],
    FILTER(ALL('SDBR StgDeParaMercado'[RB VS CONC]),[Rank Brand] <= 100)))

Which calls...

% Price MS = DIVIDE([Price Market],[Price Brand])
-
Price Market = CALCULATE([Total Price (DDD)], 'SDBR StgDeParaMercado'[RB MARKET] = 'SDBR StgDeParaMercado'[RB MARKET])
- 
Price Brand = CALCULATE([Total Price (DDD)], 'SDBR StgDeParaMercado'[BRAND_DESC] = 'SDBR StgDeParaMercado'[BRAND_DESC])

I didn't understand the logic behind equalling the same column inside the calculate function. However, if i remove the equalling of "Price Brand", or if I remove from both Price measures, the graph looks like this:

And I need to replicate the same logic to make another similar graph, only changing the legend. But, even if I keep the calculate function equalling the same column inside the Price measures, in another graph visual on another page, I keep getting the last result, like the above image.

Could you guys help me understand the logic behind this? I unfortunately can't contact the person who made the report because they left the company.

Thank you very much!