Sum of max in Excel Pivot Table - excel

Question

Please do not mark this as duplicated of Sum of Max in PivotTable for Excel because there is no even answer for it.
I have a pivot table of items grouped by ID and month, and getting the maximum Q among all items. So the totals get the maximums as well.
+------------+---------+----------------+
| A | B | C |
+-+------------+---------+----------------+
|1| Month | ID | Max(Q) |
+-+------------+---------+----------------+
|2| 1 | A | 23 |
+-+------------+---------+----------------+
|3| 1 | B | 11 |
+-+------------+---------+----------------+
|4| Subtotal 1 | 23 |
+-+------------+---------+----------------+
|5| 2 | C | 85 |
+-+------------+---------+----------------+
|6| 2 | D | 6 |
+-+------------+---------+----------------+
|7| Subtotal 2 | 85 |
+-+------------+--------------------------+
|8| Total 85 |
+-+---------------------------------------+
What I want to do is still get the max of each ID, but the totals to be the sum of the maximums. Like the following.
+------------+---------+----------------+
| A | B | C |
+-+------------+---------+----------------+
|1| Month | ID | Sum(Max(Q)) |
+-+------------+---------+----------------+
|2| 1 | A | 23 |
+-+------------+---------+----------------+
|3| 1 | B | 11 |
+-+------------+---------+----------------+
|4| Subtotal 1 | 34 |
+-+------------+---------+----------------+
|5| 2 | C | 85 |
+-+------------+---------+----------------+
|6| 2 | D | 6 |
+-+------------+---------+----------------+
|7| Subtotal 2 | 91 |
+-+------------+--------------------------+
|8| Total 125 |
+-+---------------------------------------+
I can't do the trick of this video https://www.youtube.com/watch?v=URfAkq0_dj0 because:
I can't alter the DB.
The origin table is in the data model so I think it's the reason why I'm not able to select a custom subtotal (Not sure, correct me if I'm wrong).
Any ideas?
Oh, also I'm open to use VBA.

Answer 1

You can't do it in pivot. But if you can add helper column to source table, you can use following array formula to calculate MAX value in group and then use this column in pivot:
{=IF(SUM((A2=$A$2:$A2)*(B2=$B$2:$B2))=1;MAX((A2=$A$2:$A$15)*(B2=$B$2:$B$15)*($C$2:$C$15));0)}
Change semicolons to commas if needed.
Array formula after editing is confirmed by pressing ctrl + shift + enter

Answer 2

Assuming your pivottable looks something like this:
You can right click the subtotal line, go to "Summarize Values By" and select "Sum":
Which results in: