Yup, that's a great chart. Either take the DAT at the end of the Spring/ Beginning of Summer of your Junior year, or the summer after you finish Ochem. DAT scores are good for 3 years, so if you take it after your sophomore year (if you finish Ochem then), you'll still have 2 application cycles to use them for when the time comes - but that's up to you, it's really not too bad to go back and study it again.
Good luck!