Hi SleepDeprived,
Various zoning systems can be very useful and worth considering for people who have more challenging circumstances or sensitivities, body types that are more difficult to “match” to a mattress, or who have a history of having more difficulty in finding a mattress that works well for them. It’s not that unusual to find zoned innersprings (including pocket coils) or other types of zoned support cores (such as latex) as well that have a softer zone under the shoulders. There is more about zoning in this article and in post #11 here.
Phoenix