This is a pet peeve of mine so please bear with me while I clear up a misconception that many people have. What weighs more - a pound of feathers or a pound of bricks? They both weigh the SAME! A pound is a pound is a pound. What is different? The density is different. Muscle and fat weigh the same. A pound of muscle = a pound of fat. The density is different however. Muscle is more dense (ie takes up less space/volume) than fat. So you may gain weight but lose a dress size when you gain muscle b/c you're tighter and leaner.

 Here is a great photo to illustrate this taken from this site. 

Look at the two men below. They have a lot in common. They are both 6feet tall. They both weigh 250lbs. They both have a BMI of 33.9. The body shape is VERY different between the two men. The buff man in his skivvies has a much lower %body fat than the man on the right. He also takes up much less space ie is more dense than the man on the right. Body composition is more important than the number on the scale and is more telling than BMI.

I hope to have my actual BMR determined as well as body fat and lean muscle mass measured at some point in the near future because the simple scale just does not give a complete picture.