Here are back to back packaged plays where we can see how CAR used the extra half man in the box. One of the reasons teams started to play man coverage against Chip is because of his use of Packaged Plays (or Run Pass Option play). CAR is primarily a zone coverage team and this is how RPOs can attack zone.
The 49ers put 6 blockers on the LoS (5OL + TE). CAR matches up by putting 7 in the box. But they sneak half a man into the box (orange). Is orange lined up over the slot WR or is he considered 'in the box'? He's actually trying to do both.
Gabbert sees that orange is not committing to go in the box so he hands off to the RB.
Decent +4 gain although it took some bouncing from Hyde.

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This is the very next play of the game. Everything looks the same from the formation of the offense to the alignment of the defense. It's actually the same play, but the result of the play is very different.
Gabbert sees orange is not committing to the box, but by orange trying to play both the box and the slot, he can't play the slot.
You can see that at the time Gabbert throws the ball, there are OL blocking downfield. That's because the OL isn't pass blocking, they are run blocking in case there's a handoff. I thought the 49ers could have done more of this. Not sure if they did and it didn't work, or they didn't try. Point of all this is that Chip has gotten some flak for running too much on 1st down, but the reality is that some of these runs are determined by Gabbert, not Chip.