I guess it should be quality > quantity, but does it matter whether to write to the maximum word limit?
For instance, if the word limit is 300 but you only write 270, does it mean to the admission officers that you’re not interested in the school enough to write more, or does it really not matter?
No.
No, that’s fine.
Short and concise is good. Just make sure you’ve said everything you want to say.
Don’t add fluff to a solid essay in the interests of meeting a maximum word count.