Emma, ICSI is exactly the same as IVF except after egg harvest a sperm is injected directly into each harvested egg. With regular IVF the sperm and egg are left alone in a petri dish to do their thing.

Also, there are different IVF protocols. Not all require down regulation. All mine, for instance, have been antagonist cycle which doesn't require a month on birth control pills to start.

Hope this helps!