Hi Lisa,
I have had 3 IUIs and there is a website that is really good about explaining it. It is
http://www.fertilityplus.org/faq/iui.html
27 million is really good for IUI. One of our IUIs, the docotr said DH count was 20 million, he said that is great because we only need 10M for IUI. If you are really irregular, I bet they start monitoring you or put you on some meds to help regulate you so you can keep your cycle regular. Plus, the RE will look at your history and see if PCOS is a possibility or maybe even prescribe clomid.
I really have had no problems with my IUIs, they take about 2 minutes and feel pretty much like a normal OB exam.
Good luck! I hope it works! 27 million is really not so far out of normal!