Have you been filling in a food diary to give to your consultant? If there's anything there that might stop you (for instance, not having 1/3 plate superfree if you're following EE) he or she will be able to flag it up from a food diary.
Also, I know it sounds silly, but are you eating enough? I find on weeks that I'm super busy, and thus eat less, I tend not to lose so much, and this seems to be true across all my friends following S/W.
Another factor to consider it bloating - if you're hot having your HeXB choices, it can lead to bloating, which isn't going to help your weight loss any, and same with it if it's been you 'star week' either of those weeks.
Also, are you using your syns correctly? Make sure you're really calculating the values and weighing/measuring anything synned correctly, as not doing this can add loads of extra syns you weren't accounting for!
If you're doing all of this, why not give your consultant a ring and chat things through?
Hop this helps!