Oh, hmmm.
Now that I read the OP again, I suppose I took a conceptual look at it rather than a literal one. (so apologies to the first replier as well)
I assume the question was intended so that the best player on the opposition got more defensive attention - which is the idea of the box-and-one defences. Literally: maybe they have their man marker and the nearest zone defender on them sometimes = a double, or at least that closest defender is affecting other things (driving / passing lanes) more than they would in other defences. Can we call that 1.5 men on him?
I don't know. I can say that when I've used it, it has targeted the intended player and somewhat stopped their efficiency. Maybe there is some element of doubling but the game viewer text just doesn't show this?