(Just guessing here, but the splices have strength in a linear pull. Looped over a MSH the splice will be pulled in a direction that tends to separate the strands and greatly derate the strength. At least that's my guess.)
You are correct about separation of the strands....but the separation is minimal,and the amsteel corrects itself fairly well after weight has been stressed. I don't anticipate more than 300 lb strength, but im 175 and it works very well. Has anyone else had problem adjusting there whoopies when they are wet?