ARAM minions are faster than advertised

I did a test and concluded that the numbers stated on the ms stats tab do not match the in game experience. At 425 I should be drastically outpacing a minion at 325 and instead I am barely keeping pace. Other champions can move faster or slower, but my tests show parity to minion ms at practically any number within 100 ms. I would love for Riot to post a video showing how ms is calculated an done because many of my replays will show that is not the case.