I'm playing this under v4.1 rules.I think that's the right total. Using small arms from a distance to shoot up guys in well-built trenches is just going to fail.
Do the trench hexes still get a further -2 column shifts to area fire, on top of normal terrain and dug in status? So that's -7 in total (protective and dug in and fire mode is -5, and a further -2). And El Bastion get another -2 shifts. Or was this one of the things that changed up from v3 to v4?