Two Z-series Sub but different dials, it happens but why?

[wandyprawira]

I have just noticed that in my possesion of 2 Subs (both of them are Z-series), they have different dials.

Differences that I've spotted so far are:

1. Different font style
2. "1" on "1000 ft"
3. "3" on "300 m"
4. "f" on "ft"
5. The character spacing in "000" on both 1000 ft and 300 m.
6. The font type of "0".
7. "C" on "Chronometer" and "Certified".
8. "L" on "Superlative".

Anyone know this before on a Sub? Can anybody tell me why they have differences eventhough they are in the same serial?

I know that this kind of thing also happens on GMT for the font type of "II" and "||".

Thanks in advance guys. Padi, JJ, Bo, anybody who loves Sub, I really count on you guys.