If blacks are more likely to come into contact with whites than the reverse then it would follow that blacks are more likely to be killed by whites than whites are by blacks.
I don't know if percentages are the right metric to use here. You can certainly make up a scenario which is completely absurd, but still has your percentages. Assume 100,000,000 green people, and 100 blue people on a distant planet. Nine blue criminals kill 9 blue people. One green person kills one blue person. So that's 90% blue-on-blue murder, and an 10% of the blue population are murderers, and there is a 10% murder rate among the blue population. Now lets say there were there were 9 green people murdered by 9 green people, and one 1 green person murdered by 1 blue person. Again 90% green-on-green murder, and a 0.00000001% murder rate.
It would be a mischaracterization to imply one is extremely low, while the other is much higher. They are both, comparably, very low.