Make your mind up. You said it was two days work in another post. Even if you can squeeze a two day job into one day you should still charge two days money for it, it's you that's going home knackered for the benefit of the customer. you've also got the issue of being cream crackered the next day after a 12 hour day. You can't keep doing 12 hour days without it starting to affect your performance.
What happens when your powerflush machine packs up after you've been not charging for it's use? You've got to replace or repair it out of your own pocket.
IMHO you need to revisit your business model as it sounds to me you're heading towards being a busy fool. Work for a good price and work sensibly. I've done the 12 hour days, 6 days a week before and I'd then spend half of Sunday akip on the sofa because I was knackered. Don't live to work, work to live.