Each placement is different, so it is tricky to develop a design pressure factor applicable across the board. With enough field investigation, you can come up with dependable data. More hotly disputed is how critical is the need for research. He nevertheless sees a need for more research. Designing for a full liquid head may make some see red, but it removes concern about field exigencies, which can wreak havoc with an engineer's limits on formwork.
Standard practices pack more pressure into the cooker.
Typically, the formwork package goes out months before the concrete is cast. That's if there is a superplasticizer indicated. Sometimes, the specifics of the mix are not known. More likely, say some engineers, it's not viewed in the best interest of the contractor to tell the formwork bidder that a superplasticizer will be used. It's a game of don't ask, don't tell.