What is Wrong with the Ecohouse Challenge?

I've been watching the Ecohouse Challenge on SBS regularly. I've just watched the third episode. What is the Ecohouse Challenge? The series overview explains:

Can we save the planet? To find out, two ordinary suburban households have been wired to monitor their every eco move.

The challenge starts with a bang. Without warning four environmental hotspots, energy, water, transport and waste removal are shut down until further notice.

Over several weeks, while still living their normal lives, the families must radically reduce consumption and learn to live sustainably.

For the Edwards; a large, frugal family led by logistically minded ex-commando Spike and no nonsense working Mum, Mary, it’s going to be tough. With seven in the family, including their elderly grandmother, Nonna, consumption is high.

Meanwhile the Shepherds; an affluent family headed up by financially obsessed businessman, Cam and sharp witted domestic workhorse, Shauna, love the good life. Going without is not going to be easy for these consumer addicts.

But help is at hand. The families’ Eco Coach is modern day greenie and scientific number cruncher, Tanya Ha. Together they have just weeks to do what we all must do in just a few decades. If they can pass the Eco House Challenge and help save the planet…so can we.

The two families had their electricity turned off and were told to reduce consumption by 60 per cent. The Edwards family did everything correctly. They were totally frugal, and yet they failed because they only managed to reduce consumption by 45 per cent. The Shepherds, on the other hand, seemed to have a very poor attitude to the whole challenge and didn't seem to care. Yet they passed. They were able to lower consumption by more than 60 per cent. Tanya explained that the Edwards faced a difficult challenge because they already used little energy, and so reduction by 60% was going to be difficult. It is entirely possible that, say, the Shepherds used 100 units of energy and lowered it to 40 units, which is a 60 per cent reduction. The Edwards may have been using 20 to begin with and they lowered it to 9 units of energy, which is a 45 per cent reduction. At the end the Edwards use less energy, 9 units compared to the Shepherds' 40 units, yet the Shepherds' high initial energy use means their percentage reduction of 60 is greater than the Edwards' percentage reduction of 45 per cent. This game then punishes families for being frugal in the first place. If you are an energy waster you can win this game easily simply by turning off all your luxury appliances, e.g. dishwasher, etc. But if you are already living frugally you have to turn off necessities just to win. You have to turn off lights, spend only a few seconds opening the refrigerator door, etc. Totally unfair.