Reading that thread you posted clears it up I think, I did read somewhere else that it can take a while for the oil to return from the head and this varies between different cars (can't find the link now).

Enough people on that thread suggested it is nothing to worry about so I'm going to make sure my oil level is never above the max line on dipstick, I don't have any running problems (touches wood, rabbits foot and prays to god) at the moment but I am going to be booking in a tuning session with MA developments next month so will ask them as they will know if anybody does whether to worry about it or not.