Good Lord, I'm amazed at how many posts there are on this issue!
If the directions say 250 words, limit it to 250 words. Those kinds of instructions are crystal clear. If you choose not to follow them, it tells the adcom that either 1) you don't understand clear instructions or 2) you think they don't apply to you.
It can be tough to limit yourself, but it was on the personal statement in your primary too.