I don't see any reason to suggest that if you don't let her rip just as soon as you hit anchor you must not be shooting instinctive.
I have no aiming system other than my formerly hair covered computer, and where it tells me to point my hand. I happen to think the best way to discribe instinctive shooting as looking and pointing the hand(bow hand)I shoot pretty quickly when I have to, I always hit a solid strong anchor, fast shot, or slow deliberate.
I have increased by holding time to a general two seconds. I find I shoot more consistantly when I do that. In fact when my groups are opening up, I make a concerted effort to hold longer, and it works for me.
I would have to say, it is not how long you hold that dictates what method you use. Some type of anchor point is required, no matter what it is, or where it is.