My previous 45 to 60 minute times to achieve a large temp bump-up (224 to 350) when finishing off a prime rib per Smokin's method were resolved after talking with Cookshack and their recommendation to switch to Cookshack's pellets. As they say and I now believe, there are some pellets out there that just don't perform very well. If I use their pellets I can usually now achieve a 125* temp bump-up in about 20 minutes or so. Talk to Cookshack about pellets to get their opinion on Lumberjack brand.
I think my FEC100 also went thru some strange temp displays when taking so long to ramp up the temp. It does not do it now - can't say why not any longer, but may be it just does not like using those "bad" pellets. Yes Cooshack's pellets are a bit spendy when freight charges are added, but for me their performance is worth it. And yes I do go thru lots of bags of pellets now that I bought the PG500. I just buy in large quantities (1000#) which brings the per pound cost down a bit, or at least it seems that way.