I am interested in recipes like pulled pork, lamb etc but don't have a slow cooker. I have seen recipes that say to slow cook e.g. Mk half (not even 1) for 4 hours. Whilst I realise that is very low...4 hours seems a long time to have an oven on. What I am concerned about is the amount of gas used (via the gas bill). Is 4 hours at this low setting say, the equivalent of about 2 hours on Mk 6 ish, i.e. nothing to be concerned over?