You do have a point, to an extent but it gets enormously complicated.The figure quoted represents the 'operating profit' made in the residential market and is fair to say that the rise was 5 fold.Yes you can express any number of financial ratios which will reflect a slightly different measure.I think you have chosen to use profit/turnover and that will of course dilute the answer,because the turnover is absolutely enormous.Equally you could have asked for operating profit per customer where the figure went from just under £6 to £36 (a six fold increase).
I think MS are just reflecting and generating interest around the increases.I wouldn't be too picky about that as you have explained there is a mass of data which can be analysed to paint a picture depending upon your viewpoint.I can guess what the poll outcome will say as I am sure you can.