I ran some tests on two aspects of this file (altering Senate mission distances and frequency of officeholding), but didn't pick up on the ability to assign more than one person to the same office - worse yet, I assumed it was impossible! Here's a link to my thread on this subject:
https://forums.totalwar.org/vb/showthread.php?t=44428
I ran an additional test and was able to have 4 Quaestors, 4 Aediles, 2 Praetors, and 2 Consuls all holding office at the same time (which is extremely cool!) The only noticeable problem is that only the name of the 4th Quaestor is visible on the office scroll, but that's a pretty minor glitch - everything else seems to flow normally. Assuming nothing else is changed, here's how to add additional officeholders (in this example we'll bump the number of Quaestors from 1 to 4)
Begin_Offices
Quaestor
Rank 10
Quantity 4
Duration 8
Sittings 1
Restrictions
End_restrictions
Senate_benefits
End_senate_benefits
End
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