Last 12 months by SQLBI problem

[Pbiuserr]

Hello,
I've created exactly what's here Show last 6 months but for last year (-13) and it works good, however if I have current month (so today is April) it goes from April 2022 till March 2021, so last 13 months, not 12. If I change to any other period it works good

Any idea how to overcome that? I can see that it gets "Ordinal -1" - i dont know what it is, perhaps its that what casues the problem?

Current month in slicer:

Any other month:

[amitchandak]

@Pbiuserr , Can you share the formula you have used

//Date1 is independent Date table, Date is joined with Table
new measure =
var _max = maxx(allselected(Date1),Date1[Date])
var _min = eomonth(_max, -12) +1
return
calculate( sum(Table[Value]), filter('Date', 'Date'[Date] >=_min && 'Date'[Date] <=_max))

[Pbiuserr]

@amitchandak 
hi
alike in video, its calculated group. i know there are other approaches but Ive used the one presented in the clip and If I'd need to reverse it, then it would be too much time consuming so I rely on that

VAR NumOfMonths = -13
VAR ReferenceDate = MAX ( 'Calendar'[Date] )
VAR PreviousDates =
DATESINPERIOD (
'Period prev'[Date],
ReferenceDate,
NumOfMonths,
MONTH
)
VAR Result =
CALCULATE (
SELECTEDMEASURE(),
REMOVEFILTERS ( 'Calendar' ),
KEEPFILTERS ( PreviousDates ),
USERELATIONSHIP ( 'Period prev'[Date], 'Calendar'[Date] )
)
RETURN Result