I recently worked on some documentation of the available fonts and glyphs on all four devices, and there should not be a difference in the font *sizes* between the simulator and the Epix for any of the various font sizes, number or otherwise. I did not do a screen to screen comparison between the device and the simulator (yet), so it's possible that there are some rendering differences. I know of at least one instance where the 920 appears to use a slightly smaller kerning value than the vivoactive with a custom font, and that's under investigation.
I'll do some direct comparison between the device and the simulator, but I may not be able to get to it until next week.
Sorry if it seems I keep hijacking your threads KOULIK ;)
On the Epix device, there is no difference between fonts : FONT_XTINY, FONT_TINY and FONT_SMALL.