there are lots of reasons to go thinner on a standard market car.

the weight changes in the newly refaced sedan could have effected handling, then as a carry over part in the factory they changed them all. The change in spring rate, or upgrades bushing could allow it to be downsized,

it could have bee adjusted to reduce or increase steering response (oversteer/understeer)

we are talking about the general market comfort though, not performance.