No, as long as you get your money to them before the end date everyone is treated equally.
In terms of scale back for oversubscription, I haven't read the fine print on this SPP but generally requests below a certain (low) amount of shares will get approved to keep your regular punter happy. If it's oversubscribed they will cut back the large requests near 30k first. It all depends on how many shareholders take up the offer.
