It all started with the now very old 20% resistors. The values were chosen so that going from one value to the next one would always result in an increase in resistance even if the first value was 20% up and the second value was 20% down. With such a wide tolerance it makes no sense going for values more precise than two places.
When 10% and then 5% and 1% resistors came in there were opportunities to "fill in the gaps" hence the different series. The formulae is an actual description of the process but doesn't reflect the fact that only two significant places were used. In other words 4.64 is 4.7 when rounded up for two places.