[Slyfox]

I would make sure they are all of the same lot#.

 

[rossfingal]

Yes, try to make sure that they're all the same Lot #.
However, because of availability (or whatever reason) -
if you get a couple of "Squares" of a different Lot # - try to distribute
them over the roof.
Preferably, in the back - or some, other unnoticeable area on the roof.
Better that, then - some big "Blotches" of "discolored" shingles in the middle of the roof - where they stand out.

rossfingal