I'm just chiming in to say, yeah, the logic of this is directly in line with the statistics, and economics that I learned in college. I drifted away from it and I haven't run the numbers myself, but I have no reason to doubt the calculations.
I agree with you, and I'm hoping that will reinforce to others that this is far more complex than most people can comprehend. It's certainly more complex than what the Whitehouse economists seem to understand.... Regardless, I think you said it perfectly with "exponential equations run away fast", and I think that might even be understating it; especially that the average person doesn't "get" how quickly compound rates can increase the costs of things over time.
I understand that they have to set limits for themselves or they'll be doing calculations all year and never get enough done to have the whole picture. What they are working from is certainly not the whole picture. Regardless, the math doesn't lie.
If things keep up like this, I think that in less than one quarter, we'll see the numbers skyrocket.