In this recent thread we discussed how you need a scale that reaches 150 or 170 to dial in Magenta for high grades - use the most you can get. OP in this thread could only go up to 100.
I don't exactly know how to measure the density of a magenta filter, but I took a #4 filter and put it under the green dot on my densitometer, it measured over 2.50
So I think a CC 100 Magenta would be awesome to add...
I also think this may be a matter of interpretation. The standards are based on a specific range, somewhere like 4 to 96%... and mcilroy, you're using eyeball to interpret. So you could be counting a higher number than technically getting.