I have noticed that it usually takes more time from the time corrections are made to a quiz and it is accepted than the time between submission and corrections. Is this done on purpose?

Submit - wait - corrections - wait, wait - accept(reject)

I would think that since the questions have already been gone over that the correction-acception/rejection time would be short.

When the quiz is resubmitted, it goes back to the bottom of the queue.

If the editors have time, sometimes they will go through and see what ones they have already seen and then re-edit those. (There is generally a better chance of this if the previous time the quiz was rejected the errors were specified out and the author doesn't have a history of making 'additional changes' from what the editor specified needed to be changed in the quiz. This is because the editor will just need to run down the list of what they looked out last time.) However, please note that this is an 'if they have time' and is by no means a requirement of the editor. Frequently, editors are working on many quizzes at once, so each time they have to look at the quizzes with fresh eyes as they may not remember the quiz from before.

~LadyM, FT editor

I understand and in no way am I complaining. I was just wondering what the wait would be. Thank you. The editors are doing a great job.

The wait depends on how many quizzes are in the queue, how well-written the author's previous quizzes have been and what I explained above.