Microsoft Syntex AMA

This may seem like a silly question but it's something that's bothered me for at least a decade and I've yet to see anyone even on dozens of message boards over the years answer it..... Throughout Microsoft office, the application of fonts and font sizes is consistent.....with a single exception that I know of.... Conditional formatting in Outlook gives four choices; Small, Normal, Big, Bigger. That's it. And the sizes seem to make no sense whatsoever. "Normal" renders quite small. Big is too large. Right now it shows "Normal" as an 11pt font but other items throughout Outlook also set at 11 render a bit larger. If I change it to "Big" it jumps to 14 and becomes larger than everything else, even the headings. I have never been able to figure it out why this is so. Why does it not simply use the same font popup menu used by everything else throughout Office and Windows itself? I know there are dozens of much more complicated questions I could ask. I suspect many will be answered. But this one has baffled me for longer than anything else I can think of so I thought I would ask. lol