How late is too late to take/submit DAT?

Is taking a DAT prep course for May/June and taking the DAT in July an okay strategy? The alternative would be taking a prep course in April/May and DAT in June. I think I will do better if I take the DAT later, but at what point is it too late? For example, is a 20 submitted in June better than a 21 submitted in July?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums