That seems like an internationalization bug. What was wrong with using the correct localization?
I was tempted to do more than fix the rounding problem...
... but then sanity overwhelmed me.
If you'd like to start a discussion of whether or not it is a good idea for one-thousand German bitcoin amounts to be displayed as "1.000,00", be my guest. I think there was such a discussion in the past, but I didn't pay attention to it. I think it would be nice if an amount like "1.001 BTC" (or even "1.001 tonal bitcoins") was unambiguous.
RE: subcent throwaway change: turn it into a proper PULL request (yes, you'll have to-- horrors! -- use that evil, not 100%-pure-open-source github) and it'll happen faster.