Hi ,
Create a variable as Date with formula as below
Date = todate([Billing Month];"yyyyMM")
after that use the below formula as i suggested in the above reply
= FormatNumber(Year([Date]);"0")+"-"+ If( Mod( MonthNumberOfYear([Date]);2) = 1 ) Then MonthNumberOfYear([Date]) + "&"+ ToNumber(MonthNumberOfYear([Date]) +1 ) Else MonthNumberOfYear([Date]) -1 +"&"+MonthNumberOfYear([Date])
let me know how this works
Thanks,
Tanveer.