Not sure I understand the question?

You'll have variances in every bow however slight.......any bow for any manufacturer. Slight variations in friction, limb deflections (yes actual draw weight accounts for most), etc will cause some minor changes in actual speed. It's not much really as I said most ship in the middle of the range, but occasionally a really hot one goes out so 302 (or maybe more is possible) and few near the bottom end go out as well.
I would expect the majority of the bows in those specs (26.5"/60#) to shoot in the high 290's to 300 with the exception hitting 302.........the 302 is possible but not to be expected on every bow.

To me this is such a better system of rating speed than the vast majority of companies who give you one "Approx" speed rating at 30"/70#/350 and that's taken with a bare string or a very small tied in nock set usually just to hold the arrow in place.
So the consumer winds up with a bow they think might be going say 315fps, but what is that number? The best one they tested? The Average?
The "Unaware" type consumer is also going to wonder where all his speed went when he isn't a 30" draw, or adds a peep a loop and cat whiskers etc. One number at IBO specs doesn't really help the average bowhunter/archer very much.
Bowtech will tell you what each bow will ship at with a full realistic string load and at various draw lengths/weights.

Remember when you see how impressive these speed numbers are with the Bowtech models that they are being compared to the competition's bows shooting with nothing on the string. Bowtech's bare string speed ratings would be off the charts but rather than confuse the shooter, they show what that exact bow is doing with a loaded string at their specs.
It's good stuff.