The casing is nailed to the door jamb, not the framed opening - which is how Softplan calculates it. I sometimes think that Softplan's development team should spend some time with a construction company, and see how things really get built.
One of my main issues is Softplan shows heel heights to 1/1000" of an inch, and calculates top to fascia distance, but does it completely wrong, because for some reason they think that the top of the sheathing is level with the top of the fascia.
Keith, I agree with you that they should have an abundance of field knowledge (I think all designers should) - however, I think they got this one right for the most part. The overall opening is the rough opening, 2" bigger than the specified door (for your typical pre-hung doors), and the edge of the rough opening can only be moved 3" (a stud and jack) away from an intersecting wall. This makes sense, I just think we should have the option to turn off the feature of limiting how close it can be moved.
I also agree with you on the fascia - I always move the fascia and soffit down in my sections so it looks like it's supposed to.
As far as the heel heights, maybe a lot of designer don't need 1/16" accuracy. I know in Mitek's software for designing trusses, distances are given to the sixteenth. I know when I come up with 5-11/16" pitch for a roof, they come up with the same. 1/16" in height makes a big difference over 30' of run. 1/16" = .0625, so I guess I need that 4th decimal place out.
I'm just giving examples for anyone who reads these post to think about.