They both have the same accuracy, some reason regular shots give the impression that it is more accurate, I felt that too.

You want them to be more accurate, you can change the value from .09 to .08, 7, and etc. If you are worried about your troops, you could change the minimum value, and maximum value. All in descr. projectiles. Here is a question about projectiles, does it makes sense that the archers will fire at a 90 degree angle? Archers have a minimum angle of -80, catapults have a minimum of -15. I wonder if changing it to 0 would result in less casualties of your troops. Assuming your talking about your troops getting while being somewhat in front of the catapult.
I played as dwarves, I had two units of catapults, when they were firing upon the enemy which was engaged with my troops, the catapults would kill some of my dwarves with their orcs. Even though I told the catapults to target something further off. So, I think changing the minimum fire angle would cure that.
