We tried Coromega supplements when my DS was 3.5/4 yrs old. The developmental pediatrician/former speech therapist, Dr. Marilyn Agin (co-author of book The Late Talker) recommended them to us. However, I just used one supplement in the morning, I didn't try two supplements a day.

She also suggest to try a gluten-free diet temporarily to see if that helped improve the attention, but to be honest we didn't do it at the time as we had tons of other stuff going on.

We're in the process of seeing a 2e specialist for our eg/pg DS, who's now 6.5 yrs old. Last summer our DS took the WPPSI and the tester said he had ADD/ADHD, but we're waiting to hear from the 2e specialist for a more definitive answer.
Might try the Coromega supplements again now that DS is older.