If the ribs were not falling off the ribs, or very flexible it means they were undercooked.
1. You do not need to keep temperature at 225. Low and Slow is a nice way to relax with your smoker etc, but you can also do very good bbq cooking 250-325 degrees and even hotter. A lot of the brethren here like cooking their ribs at about 275 degrees and can knock out a rack of spare ribs in 4-5 hours. I prefer to cook my ribs at 300-325 degrees and can do a rack of spares between 4-4.5 hours.
2. You can not cook bbq and get consistent results if you are cooking by a hard timeline or by internal temperature. With ribs you are looking for about 1/4in pull back on the bone, and then do toothpick test (probe the meat with a toothpick and if it goes in with very little resistance they are done), or by the bend test. The bend test is if you pick up the ribs in the middle with your hands or tongs, the ends will bend 90 degrees without breaking.
Here is a rack of st. louis cut ribs that I did last week and you can see how they bend but don't break.
For the pork shoulder/butt you are doing. Since it is boneless the way to test for doneness is to either probe it with a skewer and it will go in like warm butter, or you can take a fork to the meat side and twist. If it twists easily it is done. If it had a bone, you could wiggle the bone and if it starts releasing easily, the pork is done.