DOWN VIP responding back on TCP monitoring from 3DNS

I guess I am bit late to respond on this :) However, here is what I think is happening- if it would help anyone else having same query. With HTTP profile, the F5 is capable of looking into the request. You achieve L7 capabilities. The loadbalancing is based on the HTTP request rather than the TCP connection. This in turn means that the F5 will wait for the first request to come through, before it makes a LB decision. And as there are no pool members available, it sends out a RST. Without HTTP profile, the F5 will not wait for the request and will try to make LB decision once the TCP connection is established. Thus it sends out TCP-RST without the request coming in.