To me the FL300 choice seems curious. While it seems a huge margin of safety for MANPADS, it is not remotely safe for even medium SAMs, so must not contemplate them.
I'm no artillery expert, but a quick review of sources on the net suggests that FL300 is very conservative for 155mm Howitzers (see
155mm graph), but only a little conservative for ex-Soviet 122mm artillery, or for original model 122mm "Grad" rockets, and not conservative at all for some of the Grad upgrade revisions when operated at maximum range.
My personal guess is that this is not hyper-conservative MANPADS provision, but rather directed at some form of artillery (accidental conflict, not intentional use as AAA) concern.
A better-informed guess than mine might be useful here.