If you clipped every single BioII by 1 second, you would end up with 1/5th of a GCD saved every 3 minutes. You would lose a GCD every 15 minutes.

If you clipped every single Bio I (why would you, instacast) by 1 second, you would miss .6 of a GCD every 3 minutes. You lose 1 GCD every ~5 minutes.

It really, really does not matter.