diff between two Avg YTD Measures

Dear Community

I have on my hands two formulas that allegedly represents Avg YTD:

1st:

avgYTDV1_Measure = 

CALCULATE(AVERAGEX(VALUES('Date'[Monthnumber]),AVERAGE(OPS_ParetoTbl[MTBF])),
     FILTER(ALL('Date'),
        'Date'[Monthnumber] <= MAX('Date'[Monthnumber])
    )
)

2nd:

Tot_Measure = AVERAGE(OPS_ParetoTbl[MTBF])
//---------------
AvgX_Measure = AVERAGEX(VALUES('Date'[MonthNameShort]),[Tot_Measure])
//--------------
avgYTDV2_Measure = 
CALCULATE([MTBF_AvgX_Measure],
     FILTER(ALL('Date'),
        'Date'[Monthnumber] <= MAX('Date'[Monthnumber])
    )
)

Result:

while [avgYTDV2_Measure] is technically the correct one why is [avgYTDV1_Measure] isn't giving correct numbers??