When modifying batch size I have also noticed crack happening sooner. Fan also has to be adjusted to compensate but I don’t recommend altering batch sizes from the 40-60g range as these perimeters were set by The Creator and we mustn’t alter the divine will. Jk. But seriously changing the total mass touches upon a lot of variables and it would be easier but not cheaper. I’ve also noticed a difference between 3-5g differences in the 50g range. Though slight but apparent.
Your roast flavor is prob because the bean was stuck or there was too much convective heat and not enough bean mass that the beans could “cool down” or dissipate their extra heat by transferring heat to cooler beans via conduction. Also I’ve noted contrary to popular belief that the internal bean cooks faster than the external. So even though the drum will make a prettier bean I believe that once fully capable the air roaster can make a better tasting bean. My profile really rides the line between over and undercooked so slightly altering one way needs to be compensated or else you may not even hear first crack. Drastic changes can be made but as long as the basic formula is kept it should be a nice profile. Albeit a very difficult one.
I have no idea if this would work. Maybe try it on something else first. This is a slight variation when I was working on shortening the A.