I have a college acquaintance whose writing is unparalleled (although English is not his major), and he amazes me with his mastery of the English language every time (and his teachers, since HS, never less than an A on a paper).
I asked him, and although he's not familiar with medical school or the process, he says that in the real world (i.e., to get a job), if you want to write something to impress, NEVER use the same material twice. In fact, he goes so far to say not to look at your old statement so it can't influence you this time around.
I dunno if it helps, but I'm going to take his advice. I think writing from a 1+ year improvement (hopefully) will make you write better, and since the past is more diluted, make you focus even more on what stands out and is important in your resume.
My 2 cents.