I think his cap hits are relevant to the discount theory. The agents are call experts, I'm sure. They have to know if a team is bullshitting them or not.
With that assumption, his agent could have easily said 9.5 million in savings is to much for the most clutch super bowl winning QB in the league. Instead of 13.5 and 20 million in cap hit over the next two years, make it 17.5 and 30 because that's still a tiny hit for a QB and you can afford it. And there's voidable years. Some of the money in those voidable years is lost when the team voids them. Which means the $43m isn't really $43m if (when) we void those years or restructure.
We've all talked about what a distraction Rodgers is, how selfish and focused on his own statistics he is even when it's to the detriment of his own team and his own success. If we know it, the team and the agent knows it. Coming off a super bowl win specifically because Stafford is a bigger risk taker and more clutch, he surely could have squeezed several million more out of the team. He's sure as shit better than Josh Allen and Dak Prescott, but he took Allen and Prescott money. If you're not just trying to be right, this isn't hard to figure out.