Lately I have noticed that some players, usually those having joined the tour recently, try to schedule matches without offering times themselves by simply asking "When can you play the match?", "When do you have time?" etc.
If you think you are "guilty" of doing this or you are simply new and did not know of what ITST expects, please take a look at the following topic:
Arranging Matches
You can also provide times in a different time zone, but make sure to tell your opponent in which time zone you are giving him the times.