Rolling sum for last 3 months giving same value as current month

I found a solution to my problem,
1.I created a calender series table first which has start of the month dates only. added relation to the fact table
2.I created a measure for actual sum value
3.Then using a measure i computed sum of 3 months including current month
4.Then using a measure i got the previous month value from measure (point 3)

Reference : https://community.fabric.microsoft.com/t5/DAX-Commands-and-Tips/dax-for-rolling-average-of-last-3-months-excluding-current-month/m-p/2180555