Cash Flow statement

Hi 

Hoping that someone can help me with forecasting cash flow into the future.

I have tables a lot like this previous post https://community.powerbi.com/t5/Desktop/Generating-CashFlow-Forecast-Tables/td-p/532761

Basically a list of accounts with an expiry date and a monthly cash flow with start date being today.

What i'm struggling with is getting the totals correct when i'm grouping the months into quarters.

Monthly Drawdown =

CALCULATE(sum('Datatable'[MonthlyDrawDown]),

FILTER(ALLSELECTED('DataTable'),

'Datatable'[Expiry] >= max(Dates[Date]) &&

'Datatable'[EOM] < max(Dates[Date])

))

 

When i look at this by quarter the value is the same as the previous month.

I've tried to use the logic in the Rob Collie excel users guide but i can't get it to work.  Can anyone help at all please?