You are quite correct, I noticed that too. However, I think that the Coolah location is correct, and the reference to Cooyal is a mistake. It is certainly something you need to consider, though.
Benjamin Rowe was appointed as one of the trustees of the Coolah common, along with three Coolah local bigwigs of the time. The same three, without Rowe, were appointed to a committee to establish a school.
Cooyal is quite close to Mudgee. If that was where he lived, and he died there, his death would surely have been registered at Mudgee, not Coolah. He might have lived at Cooyal, and fallen off his horse, or been bitten by a snake, at Coolah. Or vice versa.
Perhaps the OP can enlighten us as to what his death certificate actually says, and what kind of assets he left in his will.