Welcome to the forum. Happy that you found us.
Although I am glad that you have an iron you like, the MPF is not an error on the R9. The numbers are the numbers and the mass and dimensional characteristics on this iron do not lend themselves to a high playablity rating based on our formula. Even though the MOI is high, that is only about 10% of the equation on irons, if not less. You can have an iron from the 1600’s with a high MOI because of its size, or length of the hosel, or whatever, but I can guarantee you it is not very playable. Ralph explains this in his book with regards to “good MOI” and “bad MOI”. A high MOI combined with a low actual vertical cg is a positive for performance. A high MOI combined with a design with a higher actual vertical center of gravity is not a net positive to performance. On the R9 specifically, the C-dimension is relatively short at 1.207″ and the actual vertical cg is almost an inch, at .940″. It is also heel side of center. These facts in the measurements are a true detriment to playability.
Every Maltby iron we have will have a higher playability than the R9. Significantly higher, and significantly more playable. If you like a traditional profile, you might look at our TE Forged (our all time best selling forged iron), the DBM (the black finish version of the TE with 1 degree stronger lofts), the TS1 (which is a true 3 piece forging with traditional blade profile and modern stronger lofts) or the TS2, which is also a forged cavity back iron with a little more offset and modern stronger lofts. We also have been getting great reviews and performance from our newest offering, the STi2 irons. It is a heat treated Stainless Steel modern design with progressive offset and the modern stronger lofts.
I honestly believe that if you give it an honest assessment and if fit properly with the correct shaft and grip, length and lie angle, etc., any of our irons will perform better than the one you have been playing. That being said, I do understand that we golfers are very sensitive and if there is a club we have had success with, not matter what the “rating” is, it is difficult to change or convince us there is something that might work better. I still beleive that if given an honest and true test, the higher playability irons will always win out, whether they are our models or another companies. That is why Ralph developed the Maltby Playability Factor for irons – so the end user, the golfer, can compare the expected performance of different types of iron designs based the factual data contained in the mass and dimensional characteristics of the design.
Hope this helps and again, welcome to our community.