fix scoreline bonus only allowing values up to 990 instead of 1000

[barbeque-squared]

An alternate fix for #844

This probably obsoletes #903 but I'll give @DeinAlptraum a chance to test it first

Some random Pascal that probably describes better what this PR does:

writeln ('OLD BEHAVIOUR');
writeln(Floor(989.499 / 10) * 10); // 980
writeln(Floor(989.500 / 10) * 10); // 980
writeln(Floor(999.499 / 10) * 10); // 990
writeln(Floor(999.500 / 10) * 10); // 990
writeln(Floor(999.999 / 10) * 10); // 990

writeln('NEW BEHAVIOUR');
writeln(Floor(Round(989.499) / 10) * 10); // 980
writeln(Floor(Round(989.500) / 10) * 10); // 990
writeln(Floor(Round(999.499) / 10) * 10); // 990
writeln(Floor(Round(999.500) / 10) * 10); // 1000
writeln(Floor(Round(999.999) / 10) * 10); // 1000

If it's supposed to go to a 1000 at 995 already, we can change that again in a future PR if needed. This PR focuses on making 1000 actually possible.

[DeinAlptraum]

Looks good to me and works well 👍🏼