The next issue you will find with Blend Modes is "Opacity Droppings"
Anyone that uses Blend Modes...naturally uses Opacity as part of the setting. ie. the degree of blend.
(The two work hand in hand.)
Problem is.. as soon as you do this... an automatic opacity keyframe is created.
This is guaranteed to drive you nuts!
It does not work this way in AEFX . where it is more logically and practically implemented with a normal way of setting a keyframe manually.