Appreciate this breakdown, this helps clarify things
It would be a lot easier if the English speaking world hadn't reversed the meanings of . and , in decimal numbers, compared to the international standard. In most European languages, we write 123.456.789,99 -- not 123,456,789.99. If you think about it, this makes a lot of sense because then the more visible , is the character that really makes a difference, and the less visible . is the character that's only cosmetics. (Of course the Anglosphere system also makes sense, because a sentence only has one . but can have several ,.)
Anyway, if the Anglosphere followed the international system, then the traditional numbering would go from 0,4 to 0,45 to 0,5 while the semantic number would go from 0.4 to 0.5 and reach 0.45 much later. Things being as they are, the semantic numbering could in theory use 0,4 to 0,4,1 to 0,4,2 to 0,5 and much later 0,45. But that looks weird. (Just as 123,456,789 looks weird the first time you encounter it. It looks as if it was a list of three numbers, not a single number.)