Hi TCR255,
You can read more about the futility of coil counting (and how it is mostly irrelevant because of all the many possible differences in different types of innersprings) in this article and in post #10 here. The most accurate way to compare innersprings would be their total weight which would be the best indicator of their total steel content but this also wouldn’t take into account the different properties of the different types of innersprings, any insulator materials that they use, and how they interact with the rest of the layers and components of the mattress or complete sleeping system.
One type of innerspring may work well with some types or combinations of comfort layersand other components while a different innerspring completely may work better with a different combination of comfort layers and components. Everything boils down to the balance between pressure relief and support that is the design goal of the mattress along with the durability of the materials (how long the mattress will stay close enough to its original specs to continue providing you with the comfort ans support you need)
Phoenix