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I was under the impression that if the other person hasn't ordered yet (which you haven't), you were allowed to edit your actions however you wanted. I will make sure to check with my opponent next time I want to edit my orders.
It can be different for everyone, but generally the rule is that 10 minutes after you ordered you shouldn't edit your actions. Because the person could very well be on and posting actions, and if you change them while he's posting, they have no idea and suddenly they are exploiting a sub that you changed.