is that you ignore what you call the "reaction at truck pin" in your calculation. Your drawing proves the point.

Remember I said draw a force vector diagram and you will see what I mean. Well, you did that.

First drawing: load from Luff - 100 lbs + load from Halyard - 100 pounds = 200 lbs compression load.

Second drawing: load from luff - 100 lbs + load from halyard - 50 pounds + LOAD FROM REACTION AT TRUCK PIN - 50 lbs = 200 lbs compression load.