initial and temporary condition
Thanks KBP, that gives me a clue
According to Jet Transport Performance Methods:
By default, the Boeing software assumes that descent ends 1500 feet above the landing airport, and approach begins at 1500 feet and continues to the runway threshold. This definition isn’t contained in any sort of regulatory material, it’s a purely arbitrary definition that the software uses in the absence of some other definition that may be provided by the user of the software.
Since generally gears are down before 1500 feet, I was under the impression that the approach climb performance was calculated with gears down as an initial condition and then retracted. But it seems perhaps approach climb performance is calculated with initial conditions of gears as retracted. This would answer the landing climb issue in which initial condition is gear down and "gear down performance" in which they will permanently remain down.
Is that what you mean KBP?