Mmmm....interestingly usage. I think you are saying you size and prime first - off the press?.or have I misunderstood?
Actually I probably should first ask what cal your working on?
I have a size and decap die in first hole. And prime on the downstroke. Say doing 30-30 Win. Then I have a powder thru die. If its a pistol cal that can case mouth expand then i have a Lee Disc Powder measure on top to drop the charge. Of course I could also have a manual Lee Perfect installed and crank the handle. If a rifle case and I'm loading cast I'll have the Lee Universal Expander die in the second hole. Then in the third hole the bullet seater if pistol cal, or a powder die if rifle. The powder die could have a measure installed or just a funnel to drop a trickle weighed charge into. The fourth station for Pistol will have a crimp die set to straighten the mouth if headspacing on that, or providing a crimp if say for 38sp. For rifle cases there might be a bullet seating die and it may or may not offer a crimp. If I needed to free a station up to say allow a.Lee FCD die as the last operation, I'd take the case off the press to drop the powder in. Either a measured trickled charge or a powder measure dropped charge. Then the 2nd station would be bullet seating