If you have a link to a USPSA document to support that I'll go along with it. But here's a couple of my thoughts along those lines.
As I'm sure you know, the USPSA board minutes are fairly short and non-encyclopedic. The only direct mention of purpose in the BOD minutes is from the 1/22/2000: "The purpose of production division is to open USPSA to new shooters, manufacturers and sponsors."
The specific rules for Production division were formally approved at the next BOD meeting in March of 2000, but the discussion related to power factor was not included.
Of course, given that it appears Production division originated in IPSC and was subsequently adopted by USPSA the IPSC board minutes might prove a better place to work.
That said, everything I've ever read or heard from USPSA BOD members, Area directors, or shooters who were active at the time has made it clear the division was created to allow commonly used and carried 9mm guns to be competitive, and to make the sport more attractive to shooters who were turned off by the "arms race" in Limited and Open. IMHO, it worked.
a) That would then penalize someone who only owns a .40 or .45 by making them score minor.
b) That would violate principles 2 & 3 of IPSC
http://ipsc.org/ipsccon4.htm#Principles
There is no penalty for 40 and 45 shooters. They can download and shoot the same power factors as 9mm, or they can load to 165+ PF and shoot in Lim/Lim10. They can still shoot major in Prod if they want. But if they scored Production maj/min like other divisions, the 9mm would be non-competitive.