Thanks for adding the skepticism Baron. I know that the POH is to be read with caution, but in the performance numbers they show that while cruising at 6,000ft with 2,200RPM/24"MP/Fuel Flow 75pph you'd still be doing around 158 for your TAS. We plan for 145 during cruise anyway so it'd still be reasonable and quieter.
The other thing that I learned from a 17,000+hr pilot here with 4,000 on 210's is when he leans, he leans until the engine is rough and gives the Mixture a turn till it's smooth again. It's an old technique, but since Deakin says he wouldn't recommend running LOP without the proper equipment, then what does that men in regards to the "lean till rough" technique?