Here is the problem:
\message{\the\numexpr 15/10 } % <- it rounds instead of truncates!
your actual numbers were ok, afaik.
Taco Hoekwater wrote:
>
> Hi Hans,
>
> I was preoccupied, so no time to respond before you had your own
> (incorrect) solution, sorry. Your conversion is not correct yet.
> Just a moment ...