Most of the EFA bolt-actions deal 16. Grens follow this damage profile. It's also makes conscripts inconsistent. Sometimes they'll burst something down, other times they fail to hit anything like Imperial Stormtroopers.
I'm not sure if anyone has seen this, but does the cover table: "Open" just mean a different variation of neagtive/red or does standing in the open actually make you take 1.25 damage and received accuracy?
There's Open (like you said), Ice (normal everything), Water (normal accuracy, 1.5 damage), Snow (like Ice), Deep Snow (like normal Snow) and Negative (1.5 suppression, 1.25 damage and accuracy).
...now what Negative and Open applies to, that I could not tell ya since it'd depend on the maps which I have never tried making.