You lose a buff because you don't pre-plan your Geirskogul usage. You don't need to pop it all the time. You can hold it. As long as you're getting in your 3 Gks a minute, it's more than good enough.

Even in Ravana EX, any time I've lost my BotD is because of a mistake on my behalf, not the bosses. It's hard, I know, but it's doable. Very doable. It just requires a lot of thought process.