[crispyambulance]

It's a bullshit formula that can be used to justify "padding" to people that think software development (or any kind of work) is like digging a ditch or like an assembly line.

In real world projects you don't actually know "t", nor do you know how "p" and "n" are conditioned by other factors, nor is there any basis (IMHO) in reality to that "1.3" factor in front of "number of new <whatever's> being used."

It's a pity that in so many orgs people can't just be adults, trust each other, and recognize that work often takes unexpected turns.