Why they must do it?
They are counting cars of specific models, not optional equipment
Our car register counts cars, depending on model name, written in car's pasport and first registration date. Let's say, rare occasion - in passport is written "Audi 90 quattro"
- this goes to register. Also, many S2's are counted as coupes - I remeber one audi fan, who corrected passport - from "Audi Coupe" to "Audi S2 coupe"