If one launches a cluster of missiles at a target, even with 1/4 mile accuracy (being generous with that), one is going to hit some things.
The Saudi facility was several sq miles of tanks, pipes and equipment. All Iran had to do was point and shoot.
Not unlike rocket artillery.
Yes, but those tanks were hit in a pattern with all of the hits being in the same relative place in the tanks.
https://globalriskinsights.com/2019/10/saudi-attacks-dawn-of-a-new-era-in-warfare/
There is on way that was random volley fire.