That's exactly what my GP was commenting on. Instead of using heuristics like "however many it takes the CEO completely saturated with work" or assuming the CEO worth is 300x the secretary, you can quantify it. As soon as the value of the additional slack (organizational value or risk balance) is outpaced by the slack cost (secretary salary), you know you've added too much slack.

Assuming salary maps to value add, let's say if the CEO is worth 300x the secretary, he needs 300 secretaries.

I'm not sure if this comment was meant tongue-in-cheek, but wouldn't this assume the administrative overhead scales on a linear 1:1 ratio with the CEO's value? If a engineer's value is 2x another's, it doesn't necessarily mean the former uses, say, 2x the electricity/copier machine/office space. But maybe that was your point and I'm being dense.

I was more making the point that CEO salaries are crazy and unjustifiable, to be honest.