I knew these great folks here would have some good suggestions!
After reading all this, I was thinking back on when I counted calories and exercised to lose weight. I used a calorie counter to count my calories & it allowed me 1200 calories to lose weight. In addition, it added in my activity calories and I almost always ate them each day. My exercise of choice was walking on an indoor track, and I increased that over time to 5 miles daily, so I had a nice number of extra calories to play with. (and I usually used them on wine!

)
I weighed once weekly, same day, same time - first thing in the morning after I went to the bathroom. As far as I can remember, my weight loss was pretty linear. I don't remember big stalls such as what you're describing.
So perhaps adding in some extra calories would help. Worth a try, I think.