Weighted average responding to slicers

Hello,

I'm sharing the pbix file because I've searched high and low for this, as well as asking here before, but haven't been able to figure it out.

Dynamic Weighted Average Test

I'm trying for a straightforward weighted average for our DSO. To do this, I'm using the following formulas:

1. SumProduct (Column) = 

[Amount * DSO]

2. Total of SumProduct (Measure) = 

CALCULATE(SUM(Sheet1[SumProduct]),ALLSELECTED(Sheet1))

3. Weight (Column) = 

[SumProduct] / [Total of SumProduct]

4. Weighted DSO (Column) = 

[Weight] * [DSO]

The problem: when a slicer is used, the [Total of SumProduct] changes, however the [Weight] remains the same. But that doesn't make sense, since the [Weight] is directly influenced by the [Total of SumProduct] value.

I've read somewhere on here that Calculated Columns are only calculated one time at the initial creation, so they won't respond to slicers. But then what's the purpose of the ALLSELECTED filter I'm using in my [Total of SumProduct] formula if it doesn't change all the values affected when a selection is made?!?!

In theory, the [Weight] should always total to 1. For instance, the last screenshot should look more like this:

Thanks in advance and sorry for the long-windedness!!!