Ashe crit. bug?

I know crit. damage runes are probably still not ideal on her but:

"PROBABLE BUG: Critical strike damage from runes is stacking multiplicatively with Infinity Edge item.png Infinity Edge's bonus critical strike damage, rather than additively, for a maximum of 228.265% AD bonus damage (10 + (100 × (1 + 0.5) × (1 + 0.4551)), for a total of 328.265% AD instead of 205.51% AD (for a total of 305.51% AD damage) (10 + (100 × (1 + 0.9551)."

Has this been fixed or is it intended? Thanks!

Also, does anyone know if the Sorcery mastery applies to her Q or to Thunderlord's Decree procs.?

And, what is the point of using her Q normally if it only does 27% AD per arrow even at max rank (or is this bonus AD on top of a normal auto)? I know she attacks faster but you can probably get 2 normal autos in the same duration that you'd get 5 arrows for 135% total AD.

Finally, I read in the wiki that the +10 on-hit from Runaan's applies per arrow when Q is active even though it doesn't work that way with other on-hits. Is this intended or a bug?