Yet another Burndown Challenge

Hello all,

I am trying to create a burndown chart.

I have two tables...

• tblWD
  This table contains all approved time entry at a Project/Worker/Date level of detail
• tblSOW
  This table contains SOW details, including Budgeted Hours, for each Project/Worker
  These tables have a relationship based on a concatenated key of [Project]_[Worker].

I am unable to calculate [hrsRemaining] = SUM( tblSOW[SOW_Bud_Hrs] ) - [hrsApproved_RT], where tblSOW[SOW_Bud_Hrs] should be [SOW_Bud_Hrs] per Worker given filter context and [hrsApproved_RT] is a measure to calculate the running total of tblWD[Approved_Hrs] for the same context.

Issues include, no records for dates without time entry.  For instance, no hours worked on 01/01.  However, the SOW started, so the [hrsRemaining] should be 2,000 = (1,000 + 1,000) - 0 (0 being [hrsApproved_RT] at the time).
Once started, my [hrsApproved_RT] measure carries through all dates, even those without activity, but [hrsRemaining] eludes me.

Below is an illustration of the results I am getting and the goal.  I have also included some sample data.

Any assistance would be appreciated.

Here is sample data.

tblWD

tblSOW