limiting increases to 2%, 6% and 10% stabilizes the difficulty,
It's actually 2.041%, 6.38% and 11.11% as per main.cpp, lines 673-678:
if(nActualTimespan<(nTwoPercent*16)) //less than a minute?
nActualTimespan=(nTwoPercent*45); //pretend it was only 10% faster than desired -- Actually 100/90=1.1111
else if(nActualTimespan<(nTwoPercent*32)) //less than 2 minutes?
nActualTimespan=(nTwoPercent*47); //pretend it was only 6% faster than desired -- and so on
else
nActualTimespan=(nTwoPercent*49); //pretend it was only 2% faster than desired
Not that it makes a big difference.
I will refrain from commenting on the comments' phrasing.
Yes or 10%, 6% or 2% of current difficulty. I agree the phrasing of comments could be done better but nonetheless it's irrelevant.