Thanks for the reply. The ibike coast test is what trigged my post, but I thought they did it to determine the rider's aerodynamic drag.
Perhaps the coast could be done over 30 seconds to 'average out the variations, but isnt the variation with a pm due to changes in cadence and theres no
pedaling during the coast. I definately agree a pm is not necessary, but would help me to give a similar effort whether tailwind or headwind.
I live in a flat area where we use highway overpasses for hills!