Now I am going to take a stab in the dark and guess that DFC professionaly fly's long haul for Big Airways and spends too much time in the cruise thinking of ways to save a penny or two.............. but on this I could quite well be wrong.
It would be well wrong, indeed. I don't think he flies anything these days, although he probably used to at some time. He certainly doesn't fly IFR today.
There are a few people (3 or 4) on here who stir up a lot of hot air. My approach is to ignore them unless they state something which could lead somebody to waste time/money.
Pprune is quite a good forum, with some real expertise over a broad area, but only provided one avoids taking the baits that pop up with much regularity.