I don't foil typically.
At 250* it normally takes me 12 hours on my drum. I would say that from 185* to probe tender around 200* would probably take another 2 to 3 hours. If you were lifting the lid frequently checking starting at 185*, I doubt you'd ever get there. You're loosing too much heat opening the lid, especially with the flat on top and fat cap down.
Try again. I typically start checking for probe tender around 195* and usually need another 30 mins to 1 hour.
And remember, after you pull, allow to rest for 15 mins to 20 mins before wrapping and into a coooler.
Proudly Smoking on a UDS, PBC &
Accidental Winner of the 2012 "Saucy" Throwdown.