How long should short answers and essays be?

I’ve written my essays, and other people have been proof reading them. Currently, a Michigan alumni is revising my essays for Michigan; however, she advised me to shorten them. Her revisions are excellent, and I am fixing my mistakes,yet I am worried that my essays will be too short. Originally, my essays were around 500-600 words, and my short answers were around 100-250 words. I’ve only fixed the short answers so far, but I’m about to revise the full length essays. My short answers now are about 100 words. On the Common Application the suggestion for the first short answer was 100, and I wrote about 90. The second short answer suggestion was 250, and I wrote about 150. Are they too short? They answer the question and provide insight into my life, but they aren’t too long. The essays will most likely be cut down too. At what point will those essays be too short? I don’t want the admission office to think I’m a poor writer or have nothing to say; I don’t want the length to negatively impact my chances of being accepted.
Thanks.

The 150 should be upped to around 200~ ish.

There should generally be a word limit. You would want to be at least within 50 of the limit so for essays around the 600~ word mark or more is good. 500 is a little short for the Common App essay, perhaps use more description to beep up the word count?