Look at it this way. Let's say I run a widget factory. I have a worker, Joe, that I pay $1000/week to. Each day, Joe creates me a widget that I can sell for $220. That means at the end of the week, I have 5 widgets I can sell for $1100, yielding me $100 profit.
Now, we move to a 4 day work week. I pay Joe $1000. He creates me 4 widgets, still worth $220 each. I sell them for $880 total. I now lose $120 each week.
Under the current plan, it seems the guidance is that Joe will magically start working faster and produce more than 1 widget per day. If he does not, my other option is to increase the price of widgets or to decrease the amount of money I pay Joe.