It is an issue, and I would not be surprised if it is similar to a classic foible in FPS games: never peek your head out against the AI because it will hit a smaller area with the same chance as a larger area, making all the bullets land on your head with impeccable accuracy. Escape From Tarkov is a recent shooter that suffers from this, never ever peek against the AI in that one, it is always better to present your entire body as something to calculate random hit chance against.
Fair chance that when hits against the TC or exposed gunner is calculated, the hit chance is the same or atleast well stacked as if checking for a hit against the entire vehicle.