After two decades of stagnation, three years ago my interest in photography was revived by the purchase and use of a TLR. My favorite film has become
Kodak Portra 160 VC, but my nagging curiosity is ... Why didn't Kodak (and others) make this a nice round number like 200 so it would fit in a normal film speed lineup of 100, 200, 400, etc.? Is there some special circumstance in which the 160 speed offers an advantage?
I'm not complaining, just wondering.

John