Those are the rates per year, not semester (thankfully!). The printout they gave at interviews says $25,120 for IS and $54,192 for OOS. Total for four years for OOS (assuming IS tuition after the first year) is $129,552.
It also says they're considering an increase in tuition. If you look on page 25 of the booklet they gave us, it tells you the last few years of tuition, too. Mizzou seems to be increasing their tuition pretty quickly :/
@Tamsin21, I have it right in front of me so let me know if you want any other information from it.