Spark Plug replacement interval

I noticed that the MML for the 912, 914 and 916, were all updated in 2023 or 2024. They all show a spark plug replacement interval of 400 hours if using unleaded fuel or 200 hours if using leaded fuel over 30% operation. These intervals are twice as long as those stated in the 915iS MML, the most recent version of which was updated in 2021. (At least that's the latest version available here and on flyrotax.com.)

Is there actually a reason why the 915 would have a different spark plug replacement interval than all other 9-series, or is it just that the 915's MML hasn't been updated yet? If the latter, when can we expect an update?