Patchmaster issues

[Shrubby]

So last fall I bought some Patchmaster from Scott's. Sun and shade mix. I used it in a half-sunny, half shady area. By this spring it was a nice dark green and pretty thick - it worked great. So, I used the same exact stuff in some other bare areas this year. Those areas get about the same amount of sun, but the grass that's come up is a lot thinner/lighter and seems to wilt pretty easily.

Does Scott's alter the type of seed from bag to bag? It just seems bizarre that it looks so different.