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I have no problem with you subreffing the battle. You explained your tardiness the last time, and you certainly are not saying you cannot ref because you have to study for exams (and then reffing a bunch of other matches instead).
Hey man, I'd recommend buying an Amulet Coin first instead of an Exp. Share. It takes less time to buy an Amulet Coin first and an Exp. Share next instead of the other way around.