Cascade Calculation

1.  Add columns to Price table: Include all of the necessary information for the calculation (except the volume, which comes from the Sales table). Also, Add a key column like "Residential 10-25"

2. Add the same key column to the Sales table, so that it will match the new key column in the Price table.

3. Create a relationship between the two tables.

4. Create a Measure with SUMX: SUMX('Sales', <Formula>)   //Refer to attributes in the Price table like this: Related(Price[Attribute])

Calc = SUMX('Sales',
   DIVIDE(
     Related(Price[Upper Value1]
     + ([Volume] - Related(Price[Lower Limit Volume])) * Related(Price[Upper Value2])
     + Related([Lower Limit Volume]) * Related(Price[Lower Value2]),
     [Volume]
   )
) 

Cheers!

Nathan