Prior month DAX using Measure are not displaying any value

[rocky_puff]

Hi everyone,

Need your expertise on this issue. What I want to do is to get the variance between current month and last month. But now I am trying to detect the value of last month first before calculate the variance (just minus-ing the value of current month and last month). Unfortunately, the value is not displaying eventhough I have tried all the other methods that are available online. Maybe I missed something? Need your help for this one :')

Here is the fact table : Table A
We will need to take the last value of EndDateHourDateTime column as it will keep on adding and accumulate throughout the day. For this problem, we are just going to focus on the value of Defect Class = "Produced Glove". There are also ID column which I didnt include in this screenshot.

DimDateTime table : Table DimEndDateHourDateTime 

Just for reference in case you need to refer the data type available inside this table.

Measure 1 : To calculate the sum of the Produced Glove

Total Produced Glove = Calculate(Sum(A[Value]), Filter(A, A[DefectClass] == "Produced Glove"))

Measure 2 : To calculate the previous month of the Produced Glove (below are some of the failed attempts, a bit messy.. sorry)(tried parallelperiod also, but failed.. sobs)

Total Produced Glove last Month = 
var a = VALUES(DimEndDateHourDateTime[FullDateAlternateKey])
var b = DATEADD(a, -1, MONTH)
var c = Calculate(Sum(A[Value]), Filter(A, A[DefectClass] == "Produced Glove"))

return
Calculate(Sum(A[Value]), Filter(ALL(DimEndDateHourDateTime), DimEndDateHourDateTime[FullDateAlternateKey] in b ), Filter(A, A[DefectClass] == "Produced Glove"))

@ Variance = 
//var a = CALCULATE([@ Card_Date], DATEADD(DimEndDateHourDateTime[FullDateAlternateKey], -1, MONTH))
CALCULATE(SUM(A[Value]), PREVIOUSMONTH(DimEndDateHourDateTime[FullDateAlternateKey]))

Not sure, where went wrong.. my table become like this.. not displaying the value

 Need your help for this one :')