Hi Burl,
It is not required to have it in the head, the documentation used to say it was ideal to have it there but it works just fine at the top of the body.
You are free to move the <portal:AnalyticsAsyncTopScript id="analyticsTop" runat="server" /> out of the body and into the head of your layout.master file if you wish but I have a vague recollection of there being a reason we did not put it there though i can't remember why at the moment.
Hope that helps,
Joe