no if you went a week on 12/12 of light and still feed then veg nutrients then you did the right thing.

You can change them to flower feeding anywhere between the 7th and 10 day of flower light (12/12).

You do not need to flush unless there is a problem.

You have nice coverage I hope you have more room for them to grow in flower. They will double in size in flower unless you use some bushmaster stuff to stop the vertical growth.

hope that helps you some, happy growing