It is a common response when you start/increase working out for your muscles to retain water. This can lead to little change (or even an increase) in the scale, even as you are burning fat.
However, muscle and water are considerably denser than fat (check www.dailyspark.com/blog.asp?post=quiz_how_
for a great photo of this), and typically this will show up as inches lost, even if the scale is being unco-operative.
The tape is a far more reliable means of tracking your progress than the scale. And it sounds like you are seeing results where it counts.