Formula to add values from different columns that don't align

Here's one approach...

Your three Q1/2/3 tables re-arranged in a contiguous vertical stack, an extra column added to show the Q1/2/3 value per row and then converted to an Excel Data Table. This Data Table then used to generate a pivot table to group by company.

Attachment:
Sample of Excel Merge PLUS PIVOT.xlsx

To arrange pivot by Qtr then Company, just switch row-heading fields around as follows:
Attachment2:
Sample of Excel Merge PLUS PIVOT by Qtr.xlsx


Best Regards,

Dave