Need help in DAX formula

manojk_pbi JC, glad you explained it because I would have never figured that out from the information provided. Do this (PBIX is attached)

Measure = 
    VAR __Value = [December]
    VAR __ThreshMin = MAXX(FILTER('Thresholds', [Value] <= __Value), [Attribute])
    VAR __ThreshMinVal = MAXX(FILTER('Thresholds', [Value] <= __Value), [Value])
    VAR __ThreshMax = MAXX(FILTER('Thresholds', [Value] > __Value), [Attribute])
    VAR __ThreshMaxVal = MAXX(FILTER('Thresholds', [Value] > __Value), [Value])
    VAR __Result =
        SWITCH( TRUE(),
            __ThreshMax = BLANK(), __Value,
            __Value = __ThreshMax, __Value,
            DIVIDE( __ThreshMax - __ThreshMin, __ThreshMaxVal - __ThreshMinVal) * (__Value - __ThreshMinVal ) + __ThreshMin
        )
RETURN
    __Result