If you make a tiny mistake when calling a role (mi.d, /mid) it shouldn't effect whether you got it.

I've told people enough times in a match, if you make a small mistake when calling roles such as "addc" instead of "adc" or "mi.d" instead of "mid", it shouldn't matter. However, if you make a considerably large mistake such as "miff" or "jug" instead of "mid" or "jgl", then it makes sense to effect the order you called it in.