Previous 2 month before current month...

Hi Experts 

I have the following measure which give me the cumulative figure as opposed to the actual month count for Jan 20.

When I selects mar 20 from my slicer is get count or 80 when Feb 20 I get 97 and whe  Jan 20 1

When i use measure 

Measure = 
CALCULATE ( 
SUM ( Table[Amount] ), 
DATESINPERIOD ( Calendar[Date], MAX ( Calendar[Dae] ), -2, MONTH ) 
)

I get 177..when selecting mar 20...