The documentation might have that numbering, but that makes no difference in programming on the PowerPC. When we take the value 1 and shift left by 1 bit, we get 2.

That the documentation thinks this is bit 7 going to bit 6 is immaterial.

Calling the MSB "bit 1" is a tip of the hat to serial communications. In serial communication and networking, it is predominant to transmit the MSB first.

If the documentation is about a wire format, then using that numbering is correct down to the data link layer and (modulo framing considerations and such), physical.