If you use the Tanita scale on the normal setting it will give you a slightly high bodyfat percentage. If you can use the athlete mode, it is much more accurate.
Simply try to weigh yourself at the same time every day and be well-hydrated when you do so. The readings should be fairly consistent within settings.
The Tanita scales are a good motivator. Don't take anything but the weight as gospel.
"Love is the irresistible desire to be irresistibly desired."-Frost