it doesn't matter when you start it. they will send it to you usually the 1rst of the month until you have all your blocks, but as romanojg said if they don't contact you it will be a problem if you are not getting your block sand they are already giving you poor customer service.. whoever you do your BOM with should give you good replies, I would go with a different company who replies to you right away for a BOM because I have had a bad experience with a company that didn't reply to me never sent me my blocks on time, was rude to me in emails.