Hmmm, I have done ribs several times on my PBC, with bottom of ribs 2 inches from the charcoal. I have never had burnt ends like that. Confusing... wonder why your getting different results. All I can say is that I am following Noah's advice exactly as shown in his videos (Kingsford blue, lighter fluid, 20 minutes, hang ribs). They come out soooo good, and have always been cooked evenly from top to bottom.
Have you discussed your issue with Noah? Would be interesting to hear his response/advice!
Kamado Joe Big Joe -- PBC