Originally Posted by BreakPoint
Totally serious. This has been discussed on this board ad nauseum from day one of this board's existence. Do a search and you'll see.
PC600 sounds a lot better than PC578 for marketing purposes. Same for PT630 which sounds better than PT613. So Head used 600 sq. cm. which converts to 93 sq. in. instead of its true size which is 578 sq. cm. (89.5 sq. in.), and they also used 630 sq. in. which converts to 98 sq. in. instead of it true size which is 613 sq. cm. (95 sq. in.). They did the same for the 660 sq. cm. (102 sq. in.)
For marketing, it's much better to use nice round numerical names like 600, 630, and 660 than their true size numbers. Thus, the 93, 98, and 102 are just conversions from their metric marketing names and not their true headsizes.
Actually, the "98 midplus" Prestige is at or around 96.1 sq inches.