Any collector will remind you that similar tint variations have occurred in the past, with the most blatant example being the 1954 series. Initial notes were coloured very strong and vibrant, but as the series progressed, the colours became much more dull and muted. I'm not aware of any specific changeover point, but I do know that this is an area that holds very little interest among paper money collectors. The Charlton catalogue makes no distinction based on tint for any notes other than the 1974 $2 BC and BP notes which was backed up by documentation at the time and now has firm serial number ranges.
PS: You forgot to copy and paste the image code into your post.
Logged
BWJM, F.O.N.A.
Life Member of CPMS, RCNA, ONA, ANA, IBNS, WCS.
President, IBNS Ontario Chapter.
Treasurer, Waterloo Coin Society.
Show Chair, Cambridge Coin Show.
Fellow of the Ontario Numismatic Association.