Whether the numbers are accurate: I would generally assume they are, especially at schools with higher acceptance rates. There’s probably some schools with low acceptance rates that are fudging the numbers, but that’s not likely the case here.
What you’re really asking, however, is why you didn’t get into Iowa State. I wouldn’t lose a lot of sleep over it, because it’s probably not personal. Iowa State has automatic admissions criteria and (based on your previous posts) your GPA and ACT score weren’t high enough; Ferris State is a different school with different criteria and, after looking at your application, they felt you were a student they wanted on campus. That’s great!
Acceptance rates aren’t the probability you’ll get in, just how many people got in overall.