Yes, my understanding of the theory is correct based on the paper.
I think I’ve figured out where the discrepancy comes from. It looks like I misinterpreted the moisture balance graph that Rachio shows. What the rachio calls moisture balance in the graph is different from what I interpreted the graph to show. I had expected the 0% to refer to 0% of the total AWC (the PWP). So the MAD of 50% would be indicated in the middle of the graph based on my interpretation (see screenshot below of what I was expecting). But it looks like the min/max in the graph are the MAD limits. I probably didn’t RTFM enough. I guess it all makes sense now. Thanks for the responses which eventually led me to the answer. 
