There is no bad way as long as it works for you. I have never done all these "required" measurements and I think my quilts lay nice and flat. I do the sides first and then the top and bottom and I only measure the edge I am doing.
I figure it is just like making a block a little bigger than needed and trimming it to square after it is finished.
I cut the border about 6" longer than my measurement of one side and leave a 3" tail on each end. After it is sewn I trim the extra off each end to square it up and then repeat for the other side, then top and bottom.
If you need that extra assurance of a correct measurement then take as many as you want to be extra sure.
If there is a reason not to do it this way I would like to know 'cause I can't figure why not. I know this is not the most accurate way but it works for me. If there is a better way I would like to know.
Now I'm totally confused! What measurement should you be aiming for? the center or the edge?
Milliequilter didn't say anything about wanting to miter the corners so what is all the reference to miters?
I'm really confused? Old dog new trick thing!