The ostheer mortar is more powerful than the usf mortar. The further you go in the ladder the less you will see of the usf mortar. It's a 240 man power unit that has way too much rng to be reliable. It is reliable at missing mgs with its barrage, and if the barrage misses your suppressed rifles or echelon have to retreat. Usf don't have pios with superb vision.
Try using the right tools for the job then. If your rifles and RE are suppressed using smoke will stop them from getting pinned. Relying on the HE barrage which is literally RNG when a reliable alternative exists and complaining about seems foolish if you ask me.