Cam regrinds alter the opening and closing events relative to the base circle.
This along with camshaft installation angles (stock or regrind) will impact where the power is realized.
Considering that the stock T-III valve train was designed to support 8500+RPM, it's no surprise they can be installed in a manner to do so.
It comes down to preference for a high advertised peak number or a potentially lower peak for wide power bands and area under the curve.
This is how cars making less peak power with wider power bands out accelerate the narrow peaks of higher RPM vehicles.