Coil Spring Drop Question

[GOPAPA]

I have been searching through the parts for sale section looking at all the coil spring pictures figuring out how many coils per coil there are to be stock and how many coils to a 1" drop 2" drop 3' drop and so on.

I see 8 coils for a 2" drop front coil spring
I see 7 coils to a 3" drop front coil spring

And I count 7 coils to a stock rear coil spring

And I seen one front coil spring with only 6 coils and it was still rated as a 3" drop just like the one I seen with 7 coils.. are some coils heavier duty than other for the reason of the less coils vrs the more coils and still the same drop?

If some one wants to school me on this ,,have at it please because I need some schooling ..LOL gp