The 'GT5:P has covered the development costs of GT5' has been raised and destroyed before.
GT5:P has been sold at well below the RRP for the majority of its sales. Downloadable sales are for a lower price, it was bundled for a long time in Japan. There are also costs associated with the prologue that aren't covered in the 60 million rnd for GT5; manufacturing and shipping costs of the discs, as well as the fairly low costs of the code required in prologue that isnt in GT5, and hosting costs for the downloadable version.
On topic - thanks for the link. It's unfortunate we cant use it to compare to VGCHartz numbers because we dont track dl sales