Grigioperla o lavanda?

The reason yellow/orange can come (mostly in neck and shoulders) is because the subject is based on gold (s+) or when the groundcolor is not pure (not E/E) or when there are not enough black-pigment intensifiers (Ml/ML or Ml/ml+).
When a subject is based on Silver you never have this yellow/orange problem.
In the different genetic-codes of all "grigioperla" you can have this :

-E/E S/S * S/- lav/lav Ml/ML = NEVER yellow/orange
-E/E S/S * S/- lav/lav = no yellow/orange
-E/E s+/s+ * s+/- lav/lav Ml/Ml = no yellow/orange
-E/E s+/s+ * s+/- lav/lav = possible yellow/orange
-E/eb s+/s+ * s+/- lav/lav = surely yellow/orange