I guess you are not aware of the fact that while Indiana University may be required by law to interview all Indiana residents with a MCAT >22 and GPA >3.2, that it doesn't mean it accepts these students. Further down on their website, they also have a stats pdf file that states their average MCAT for matriculating students is 30 and their average GPA is 3.68. Low tiered? Perhaps. Get in with low MCAT score? Probably not.
I've also had a couple of friends who were Indiana residents who interviewed there and asked what their chances are for entry after giving their MCAT/GPA and the interviewer told them flat out it's not possible. So it seems the school interviews students who have little or no chance of getting in. Unlike other med schools, Indiana does not have control over who they interview.
As for osteo schools, I don't doubt that some do get interviewed with low 20's, but it's also highly unlikely they would get in unless they have other things going for them. People may say that osteo schools look 'beyond the numbers' but that doesn't mean they will take 'anyone'. I suggest to anyone who has low MCATs/GPAs to look at the school's averages and see if your scores far within their range. If either MCAT or GPA is below average, the other has to be above the average to been deemed competitive....for any med school in this country. So for those with low MCATs, that means high GPAs. Med school may be a crapshoot, but there is a definite pattern in who they choose to admit.
To the OP, I suggest you do as well as you can on the MCAT. DO schools typically look for around the mean, so ~25 to be considered competitive if your GPA is decent. For MD schools (in the US), a ~30 would be good. Low 20's may be doable for DO schools if you have everything else lined up right. I wouldn't suggest applying to MD schools with low 20's unless you know someone on the adcom.