I don't know. Just retread your posts a couple minutes later maybe? I just feels frustrating to make sense of them sometimes. So maybe with some time to forget what you meant, you'll be able to read your post like somebody else, and feel the frustration they feel, and remedy it?
I'm sorry if nobody else has trouble with your posts and it's just that I have some sort of problem understanding you.
Anyway... It sounds like you distinguish between two different reasons people start later than optimal:
I agree that reason 2 is more properly called procrastination than reason 1, and that anchoring-induced delays, if they exist at all, would be part of reason 1.
So, yeah, if anything, anchoring on a deadline causes irrational delay, not really procrastination.
The phenomenon of anchoring seems to predict that deadlines will cause you to start a project near the deadline.
In more detail:
Any number you consider as an answer to a question will become an anchor and draw your answer towards it. Since you consider a deadline as a time to finish a project, your decision about when you should actually finish the project will be drawn towards it.
That'll make you start the project later, even though you know consciously that planning to finish a project near the deadline is a bad idea.
It's analogous to an example from Kahneman's Thinking, Fast and Slow—people buy more cans when there's a sign telling them that they can only buy 10.
So, what I'm predicting is that anything that prevents anchoring will reduce procrastination when there's a deadline. Consciously deciding when you plan to finish by adjusting from a much earlier time, maybe?
EDIT: Brendon_Wong points out that "procrastination" really refers to putting things off, which has an emotional cause. I think he's right. What I'm talking about isn't really a procrastination, then, but bad planning.