If you work too much on a small part of a parallel text, if you try to dig out as much info as possible, i. e. take an "intensive" vs "extensive" approach, you gain locally (you can remember some words "here and now" etc.), but lose tempo overall. Intensive approach is what traditional learning books are full of, why just not use them?
Parallel texts are intended not for analysis, but for speedy reading, i. e. "extensive" approach. Their main purpose is, as I see it, to get you quickly accustomed to the foreign language you learn, so that you stop fearing and perceiving it as a frightful mess of unknown words and terrifying grammar that no one is able to remember in a lifetime.