Ooh you are lucky, being able to have a 'cheat night' and still lose weight!!
I weigh in on a Mon morning (cos I do SW at home) and therefore my week starts on a Mon morning. I don't 'cheat' and always count all my syns. If I didn't, I don't think I would be able to stay at target.
I did give myself a 'day off' a couple of weeks ago when I went away with my hubby for a night away. It was the first time I hadn't totted up all my syns since January!
And guess what, I'm still trying to shift a pound I gained after that one 'day off'!
xx