I just checked my email and saw that. This is a really generous gesture. Thanks YoYoGames!
They have also included a $20 off promo-code (expires Sept 27) creating a price of only $79.
Let's also not forget that Sandy has tweeted that buyers of GM:HTML5 will get a discount off of Studio that will atleast be worth $99.
Even if you are not interested in GM:HTML5 but are interested in Studio, you would be a fool to not take advantage of these offers.