Karma calculation not correct.

While giving karma to someone, I can see the maximum number of karma I can give, and fine tune it (downwards) if need be. That's fine.

For example, to give someone a calculated karma to make his total karma a round figure, say, 500000, this formula should hold good:

His/her existing k + my calculated k = 500000

But what I actually find is that there is always an error of (-)1, and the recipient gets a resultant number of 499999 instead. And I turn red with embarrassment. :o Perhaps the recipient would take me as a miser and indecent too. :(

There is no way provided to grant +1 karma immediately again or edit the karma already given.