Originally Posted by taxgenius
That's not what the guide says.
I think you are misinterpreting what the guide says.
The first paragraph says that the size you tell Charlie will be the middle hole in the belt he makes, so there will be three holes adjustment both larger and smaller.
Then there are three examples of how to determine which size to tell Charlie to make. I think this is where the confusion is. In #1, which is preferred, you are measuring an actual belt that you have, and you are measuring to the hole you use. This is your "actual" belt size. This measurement will be the middle hole on your new belt. So, for instance, if you've gained weight over the years and are now using the last hole, Charlie's belt is going to adjust for that and put your current waist at the middle hole.
#'2 and #3 are estimates based on clothing size. There are a few reason these are not as accurate. First, you are not measuring the belt or your waist, but rather a piece of fabric. It is not only more prone to measuring error, but you also have to account for the bulk of the pants themselves. For example, you may have exactly a 34" waist, and the inside of the pants may measure exactly 34", but when you add on the thickness of the cotton/wool and lining, etc., it could add another 1" to the circumference.
The other reason is that marked clothing sizes are often not accurate. It is not uncommon at all for pants to actually measure 1-2" more than they are tagged; e.g.: the label says 34, but they are actually 36. So if you used what the tag said, there is a good chance that you could be understating how big the belt has to be.
Finally, there is one other factor that I don't think anyone has mentioned, which is that most off the rack belts give the size to the last hole. So, for instance, a 34 belt is 34 at the last hole, but only 32 at the middle hole. This is why most stores tell you to buy a belt that is 2" larger than your waist.
Because Charlie is doing this by hand and trying to be accurate, he is going against some of the clothing industry conventions. But he is getting your exact measurements and doing it correctly.
Just remember - what you are telling him is how long the belt has to be to reach around your waist, so that it buckles at the middle hole.