I made an extremely specific prediction. I don't expect it to be totally accurate. The prediction wasn't intended to be taken so seriously. But since you seem intent on attacking it, I'll point out the flaws in your own analysis.
Out of Diaz's fights, how many times has he faced a wrestler of Koscheck's calibre, who could potentially hold him down for three rounds?
Out of all of Koscheck's fights, how many fighters has he faced with a guard that is as dangerous as Diaz's?
You can't evaluate a record in isolation, stripping it of context. You have to look at the strengths and weaknesses of both fighters.