Power Query - rolling n months, data from a n months ago, for one calendar month

ewakol 

step1 - add a custom column called FilterDate

Date.FromText([GeneractionDate], "dd-MM-yyyy")

step-2 - Add another custom column to calculate the date for last three months 

Date.AddMonths(Date.FromText([GeneractionDate], "dd-MM-yyyy"), -2)

Step-3 - Then filter the data  for two months

let
    Source = TableName,
    ChangedType = Table.TransformColumnTypes(Source,{{"GeneractionDate", type date}}),
    FilteredRows = Table.SelectRows(ChangedType, each Date.IsInPreviousNMonths([GeneractionDate], 2) and Date.IsInCurrentMonth([GeneractionDate]) = false)
in
    FilteredRows

Step-4 - Then filter the data  for three months  

let
    Source = TableName,
    ChangedType = Table.TransformColumnTypes(Source,{{"GeneractionDate", type date}}),
    FilteredRows = Table.SelectRows(ChangedType, each Date.IsInPreviousNMonths([GeneractionDate], 3) and Date.IsInPreviousNMonths([GeneractionDate], 2) = false)
in
    FilteredRows

Pls let me know if it works