I'd stall - or even gain - when I used to have Atkins bars previous times I tried this diet. It definitely contributed to me feeling jaded and giving up - and I don't know which LCM sauces but some of them contain maltitol and sugar alcohols which make them even worse than the bars. The ingredients in those things, while they magically don't take you out of ketosis will still spike your blood sugar as much as real sugar would, and then your body has to burn off the sugar alcohol as fuel before it can burn off any fat. So of you're having them a lot you just might not be giving your body a chance to get to your fat reserves.
Also bear in mind that you don't have much left to lose and you lost a lot pretty quickly, your loss does have to slow at some point.
Try a week with no bars and no sweetener except sucralose - make sure your fats are a higher percentage of your daily calories than your protein and try not to have more than the recommended 2 tbsp cream allowance - just for a week, and see how it goes xx
dieting is hard. being overweight is hard. choose your hard.