help required to write Measure

Hi 

I am writing a meaure to calculate %Change from Dec'23 to Mar'24 and display value on card. Using the below measure.

Along with this KPI, i have few more KPIs on the same report which will use the filter of the ReportingMonth. 

I want below expression should not filter based on selected reporting month and do the calculation just by using reporting month value and defined values from preMY.

%Change_CYCM =
VAR _preMY = VALUE("2023-12-01")
VAR _preqty =
CALCULATE (
SUM ( 'Bugs'[BUGS_COUNT] ), FILTER(ALLSELECTED('Bugs'),
'Bugs'[ReportMonth]=_preMY)
)
VAR _curMY = VALUE("2024-03-01")

VAR _curqty =
CALCULATE (
SUM ( 'Bugs'[BUGS_COUNT] ),
FILTER (
ALLSELECTED ( 'Bugs' ),

'Bugs'[ReportMonth] = _curMY
)
)
RETURN

DIVIDE ( _preqty-_curqty, _preqty )