Scoring rounds even! 10-10? What's the problem? More rounds should be 10-10. Fact.

[Alpha]

The round you describe would be 10-9 to the fighter that scored the knockdown.

Usually although some judges still score that 10-8. I just like the idea of a bit of variation. Like @Spicoli said there are different degrees to a 10-9 round and a .5 system in theory gives the opportunity to reflect that.