There is nothing in the book about not landing on grass so whoever did their calcs probably slipped up somewhere. Been into grass a number of times - they don’t like wet ground as it sludges up the spats/pants and the springy undercarriage means you feel all the bumps.
If I recall correctly there have been cases where the fuselage has been recycled but depending upon where they land determines the additional damage and therefore repairs that take it beyond economical repair.
Most pics I’ve seen of a SR under a canopy, even on flat ground have busted nose wheels as well as a lot of gelcoat to re do.
A couple of years ago Cirrus were running the Embark program where you’d get three days from a CSIP or CTCI if you bought any Cirrus second hand - not sure if the programme is still running or not.