Plans get added because a sales meeting asked for one. They almost never get removed, because removing one requires somebody to name which, and nobody can price what naming it costs.
Thirty-eight plans and three elevations each is 114 combinations, carrying $2.47M a year in drawing and permit maintenance whether they sell or not.
The instinct is to cut the expensive drawings. That instinct is wrong, and the model exists mostly to prove it. Pull a combination and its buyers do not disappear — most take a different front on the same plan, which is why elevation substitution runs at 95%.
Asking someone to change floor plan is a harder ask, so whole-plan substitution runs lower. That gap between the two rates decides both scenarios, and it comes out of your own buyer history rather than out of an assumption.
$32,000 a plan and $11,000 an elevation, paid every year whether the combination sells eighty homes or four.
Pull a combination and the buyers do not disappear. Elevation substitution runs at 95%, whole-plan at 85%. That gap decides both scenarios.
The share of buyers who do not substitute and leave. It is what turns a $390K carry release into a negative number.
SKU depth joined to tender volume. Not a catalogue saving at all, and it is where the case actually lives.
The rest of this model — the data sets it runs on, the cause split, the working behind the reference figure and a sample output — goes out by email. Two fields, nothing else.