yeah i decided to extend mine out longer but the WEIGHT gain slowed down considerably after about 8-10 weeks. strength increased pretty nicely before, but i've been going very strong the past several weeks. almost done with 16 weeks at this point. have been on npp as well so that helps with the strength, and i've been playing all sorts of games with my diet just to see what happens. my joints are getting used to the weight i can tell on the basketball court. again, the npp helping there, but i think that will carry over when off cycle as well as i will no doubt drop a bit of weight, at least some from water and such. i don't look smooth but there's definitely water in my muscles as well causing some of the "fullness."
i think running it out another few weeks beyond just 12 might be good for you. you've been around the same weight for a little while now, i think the extra time at the end to acclimate to your weight, to work on getting your eating right for your new weight so you can attempt to preserve as much of your gains as possible, etc., could really benefit you. but ultimately, just listen to your body and what you think makes sense. no one can run a cycle for you. in the end you're gonna make the decisions, you're going to make the changes, you're going to make the tweaks and adjustments, and you're going to learn from it. or you won't do any of that and you'll waste your money. that's on you. lol.