May be add CustomerID as your dimension here:
WeightOfAdjProb65_74_2 * AvgAdjProb_65to74_2 as WeightedCal_74_2,
WeightOfAdjProb75_84_2 * AvgAdjProb_75to84_2 as WeightedCal_84_2,
WeightOfAdjProb85_105_2 * AvgAdjProb_85to105_2 as WeightedCal_105_2;
_PCR2CalcMoYr as _PCR2Calc_KEY,
Sum(If(AgeFlag=1,NUMERATOR_PCR,0)) as Age64_105Num2,
Sum(If(AgeFlag74=1,AgeFlag74,0))/sum(AgeFlag) as WeightOfAdjProb65_74_2,
Sum(If(AgeFlag84=1,AgeFlag84,0))/sum(AgeFlag) as WeightOfAdjProb75_84_2,
Sum(If(AgeFlag105=1,AgeFlag105,0))/sum(AgeFlag) as WeightOfAdjProb85_105_2,
Sum(If(AgeFlag74=1,[Average Probability of readmission],0))/Sum(AgeFlag74) as AvgAdjProb_65to74_2,
Sum(If(AgeFlag84=1,[Average Probability of readmission],0))/Sum(AgeFlag84) as AvgAdjProb_75to84_2,
Sum(If(AgeFlag105=1,[Average Probability of readmission],0))/Sum(AgeFlag105) as AvgAdjProb_85to105_2
Where (Match (_PCR2CalcMoYr, 'PCR2Feb2017'))
Group By _PCR2CalcMoYr, Customer_ID;
You have calculated you number for a dimensional context of _PCR2CalcMoYr.
If you need it per customer (but calculated statically in the script), you would need to calculate it per required dimensional context (and maybe for different contexts).
Have a look at
of how you can create a table with facts of mixed granularity (i.e. use several LOADs to calculate your number for the specific context, and concatenate the resuls into one table. Create a key field to access the numbers for the specific context you want to retrieve in the frontend).
This can create a huge script and table though.