Guess then the issue is when is done, done? Fall off the bone just needs to cook a while longer. If they were done in 3, then try 3 1/2. Keep in mind the weight of the rack. Next time, no guarantte they'll be done in 3 1/2.
I always say, give it a try and see. Experimentation is what keeps BBQ'ing fun.
I've been a rib cooker for a long time, don't know that I ever heard 180 as a mantra, magic temp for ribs. I personally don't think there is much difference between 180/200/225 and 250 (but that's a different Smokin' length thread)
180 or 225, for me I don't see a difference, not as far as the meat is concerned.
Since you're cooking the in foil, not too much downside of them drying out (without foil they will). Longer cookers at lower temps any meat will dry out (if it doesn't have a REAL good fat layer to keep it moist)
I don't know of a specific upside other than getting more time to smoke (the longer the meat stays below 140, the longer it will allow smoke to penetrate) but I find this is okay with briskets or butts, but not needed with ribs.
I do my contest ribs at 275.
The 180 was just a lower setting on the traegers to get some "smoke". The next setting is 240 or 250 (depends on controller). They can't really go lower than 180 without the fire going out (I have the traeger controller in my FE)
And you PROMISE you'll never do them in the oven again...RIGHT???