ThomasR I give you one point for you answer on the asym/sym core answer because I was wrong on what i remembered but the argument of differently engineered vs modified I think is subjective. I am only agreeing with the OP on the cores looking the same, no doubt changes can be made for desired reactions for the intended purpose of the ball being designed.
Blazing Inferno
The Blazing Inferno is a higher RG version of the original Inferno. Even though the inner core shape is the same as the
Inferno, 1.17 pounds of weight have been moved from the inner core to the outer core. This shift in weight results in a
significantly more cover heavy ball. The RG-min of the Blazing Inferno is 0.068†higher and the RG-diff is 0.017†lower than the original Inferno. This change in mass distribution allows the Blazing Inferno to be a better match-up when reduced traction through the heads and the mid-lane are desired.
http://www.bowlingballvault.com/companies/3-brunswick/540-blazing-infernoI will however give you 1000 points and a pat on the back for being on here and answering questions. You deserve a raise or a straight jacket for that lol.