Problem with table's grand total

[nferran]

In the first picture I have an specific number of "Vacantes" and a number of "Calificados por Req" for each "Requisición".
I need to visualize grand totals.
As far as I know, I need to put these numeric columns as Metrics and check "show summary row", as in the second picture.
The fact is that I'm oblied to use aggreation in these columns, so the values are modified.

How can I mantain my original data AND visualize grand totals?

Thanks!!