Thank you, I've already tried to fix this myself (and not only me I guess):
Thread link I've played with "clip_near" and "clip_far", but no results..
I've increased number of particles (actually, when I faced problem, I was using too much of them already), same no results...
I can post my script that I use to create decals, if needed, I think I'm using them pretty properly (worked great with A7).
Plus, one more question, why does model disappear if there is a decal shadow under it?