Honestly... I don't think the exact number on the scale should matter.
What matters most is that general trend. If you are losing weight, you will see it on a scale no matter what- both at the Drs office and at home. I typically see ~3-5 lbs up (on my small body) when I go tot he Drs- and sadly, they measure me short sometimes. Once I went in, and they said 5'3.5" and I wasn't wearing shoes... the next time I go in, I'm 5'2"?! How does an 18 year old shrink like that?! I've had a lot of people try to measure me, and most of them get 162 cm or about 5'3.8". My mom told me that when they measure me at the drs, they push the thing that rests on my head down so it slopes downward a little bit. Point is, the measurements are not always right.
It isn't just that there are small measurement errors, or other lurking variables (clothes, food, time of day, etc). It's that the exact number shouldn't matter so much. Get into a healthy weight range, and then go not off of weight but off of general feel and look. You have exactly the same amount of work to do to get to your "goal body" regardless of what a scale- or several scales- say. That number is whatever the heck it wants to be. You can do whatever you want to get it to go up or go down, but that won't change where you are at the moment...
I'm rambling. Long story short: You are where you are now regardless of what the scale says. You can cheat out of the scale (or the scale can cheat you), but in the end, NOTHING CHANGES. If one scale says 170 lbs and another says 175 lbs and another says 168 lbs... You aren't gaining 5 lbs or losing 2 lbs or whatever. You are where you are and that number doesn't define where you are.
The only thing you need to look for is consistency in the same scale, so that you can monitor the basic trend (ie, "it's going down")
"One step in the right direction won't change the world, but it's a start. Someone's got to see the good in everything." -- Said the Whale, Banks of the English Bay
"Everything that you believe is everything you need right now." -- David Lanz, Whispered in Signs
| Body Fat %: 21.0