S.Peelman on 08 March 2018
I'm pretty sure the 'IIII' on clocks was done because then you'd have an even number of I's and V's, which was cheaper to produce than an uneven number of those letters for some reason. Or something, don't feel like looking it up but I seem to remember something like that being the reason for IIII instead of IV on clocks.
EDIT: Besides that Rol is right. Early Romans didn't have many rules as to how to write numbers, meaning there were multiple ways to write them. So they could use IIII instead of IV to avoid the connection to the name Ivpiter. That doesn't mean IIII was 'correct', it just wasn't 'incorrect', until later when more rules were set.
Also, the tally mark theory will only be proven right if they name BO5, 'IIII'. 
