Power Pivot Grand Average issue

[MichaelSchulz]

I have a Power Pivot table.
In the Values, I have a measure that calculates a percentage.
In the Rows, I have two fields and in the Columns, I have one fields.
This all produces the values wanted.

Next, I need one more column that shows the average of those values in each row.

The problem:
I can add Grand Total by selecting On for Rows Only but the option to Summarize Values By is greyed-out, so I cannot change it from a Grand Total to a Grand Average (anyone know why this might be?).
I created a measure that successfully calculates the average but since there is a field in the Columns section the result of that measure is also split out rather than having just one average of the values in that row.

Suggestions?

 

[MichaelSchulz]

the option to Summarize Values By is greyed-out…(anyone know why this might be?)

So I've just learned that this might be because I am using a measure in the Values area. If that's so, what are the alternatives?
Instead of placing a field in Columns, I could create measures for each distinct value contained in that field. However, the problem there is that the distinct values are variable and likely to change with the further updates/refreshes. With each update I would have to create new measures for each new distinct value. So that might not be a great way to go.

 

[RoryA]

You'd need to create a measure that performs a different calculation at the grand total level - usually done using something like HASONEVALUE.

 

[MichaelSchulz]

You'd need to create a measure that performs a different calculation at the grand total level - usually done using something like HASONEVALUE.

Since there is a field in the Columns area of the pivot table, how do I keep that measure from being 'split' by that column field?

 

[RoryA]

There’s only one measure. For each item in the column field it will show the value for that item but for the grand total it performs a different calculation. If you provide more detail, we can provide a specific example formula.