I do not know how much Insurgency is based on Real World mechanics (apart from ballistics, which seem simplistic at best), but what Hogan has illustrated is close to actuality.
The "Sight Picture" and where your barrel is in relation to it has little to do with where your shots land, beyond 100m (91yds). Below that distance and where you aim (even with minimum distance correction on sight aperture) the "Sight Picture" is then effected by it's physical location relative to the barrel, (Bore Line) but not by much.

Most normal infantry doctrine instructs soldiers to have their weapons "Zeroed In" to at least 100m (91yds) and then manually corrected for use at 300m (274yds) by "Dialing In" the rear sight aperture.
*This has been made easier on the Iron sighted M16A3/4 and late model M4's by the adaptation of large chunky adjuster dials.
Older models had plush bezels that needed a small specialized tool to manually correct for distance (Or the head of a loose round if the situation was intense enough )

So lets assume for a moment the in-game mechanics are setup for 300m (274yds) standard. (and wavering any beta bugs or abnormalities, and point blank shooting) What we are therefore talking about is "Inclined Fire".

Inclined fire is a shooting situation in which a weapon is first zeroed in at a shooting range that is level or nearly level, and later must be fired at a target located either upward or downward at some inclination angle and some slant range distance between the shooter and the target. An upward inclination angle is called an elevation angle, and a downward inclination angle is called a depression angle.

In such a situation a weapon will always shoot high compared to where it shoots on a level trajectory. How high the weapon will shoot varies with both inclination angle and slant range distance to the target. The problem facing the shooter is how to determine how much the impact point of the bullet will change at the inclination angle and slant range distance, and then to adjust their aim so that the target is hit. Adjusting the aim can take place in either one of two ways. The shooter will usually aim a little lower for an inclined shot than they would aim for a horizontal shot, in order to compensate for the weapon shooting higher. This is especially true for urban combat, because shots at moving or partially concealed targets must happen quickly. But a sniper in a situation where there is more time to prepare for the shot would probably dial a come-up or come-down on his sight, after calculating the correct aiming adjustment. (not modelled in-game)

To use either of these techniques the shooter must know where the bullet will be relative to the line of sight through the sights on the weapon at the slant range distance to the target. In other words, the shooter must know what is called the Bullet Path, that is, the distance between the line of sight and the position of the bullet at the slant range distance of the target. Bullet Path is always measured. "Perpendicular To The Line Of Sight". It is positive when the bullet is above the line of sight, and negative when the bullet is below the line of sight. A convenient mental picture of Bullet Path is where the shooter would "see" the rear end of the bullet, if they could watch the bullet through the weapon sight as it flies the trajectory. IE Tracer rounds. We make a careful distinction between Bullet Path and Bullet Drop. Drop is the "Vertical" distance between the extended bore line of the weapon and the position of the bullet, at the slant range distance of the target. It is very important to keep in mind that Bullet Path and Drop are not the same, and the shooter needs to know Bullet Path, not Drop, in order to aim the weapon.


This could of course be completely moot if there are no instances in the game this effect is modelled, and is only caused by incomplete or "Beta" programming. (To be ironed out for published release.)

For a definite answer a word from the development team might be nice, or someone "In The Know", but can be tested out in-game with non competitive testing.
A "Target" setting them selves up in various locations, both high and low comparative to the "Shooter" and assess bullet path/ drop (if modelled) and where the "Shooter" aimed to achieve the shot.


Acacios.