10-14 min seem very short for French roast. I guess it really depends on type of roaster as well. I thought typical drum roaster would take 15-18 min to get up to 460-470.
I didn't time it how long it takes after 2C starts, I just make sure that I keep the air temperature constant, monitor bean temperature and listen to the 2C till it gets very rapid. Next time I will time it. As far as roasting temperature goes, I think it does matter how soon you introduce the bean to higher temperatures. If it takes 5-7min for temp to get to 480deg F, there is no way my French roast would take only 10-14min.
You are absolutely correct, it is more and that's the reason our customers loves our coffee at the roast level they prefer. We are getting feedback from our customers that they are really happy that they are able to use dark roast coffee and do not clog superautomatic coffee makers.