I tend to still stick to plan too, but do allow myself more treats than I would have done while loosing the weight.
By that I mean, if we go for a meal, I won't stress that its not SW friendly, but would make a choice that suited my day (red/green whatever), if that makes sence.
I also allow myself more naughties, but do stick to plan mon-fri, sat & sun I am probably a little less 100% if i'm honest, but still somewhere close.
Thing is for me, i found the SW plan tought me a new eating style & thats how I see myself continuing to eat in the future. Yeah we all know take aways arn't great, but as long as its occasional & not over indulgent, so stick to plan during the day, then I don't see a problem.
I have been maintaining since June & am so far doing good. I personally don't go to WI much at all anymore, as I felt I needed to be able to take control so weigh at home now. That's something that is personal choice, some need the WI to keep on track (which is perfectly fine) others manage ok on their own.
Good Luck x