Just to expand on the issue, the elevation change was having completely different effects depending on which charge I was using. On charge 1 the rounds completely ignored elevation change, so even if the target was over 200m below the gun, I had to do nothing with that column for rounds to land on target. For charges 2 and 3 the rounds fired at targets at lower elevations landed closer than the range table would suggest, so I actually had to adjust by an amount to make the lands further, which is the opposite of how it should be. It also should be noted that the amount I had to adjust was not at all related to the numbers on the table. I can't confirm if this was actually related to the charges or if something else was going on, this was just what I observed with several targets from different charges.