needn't have

Anonymous Steve needn't have finished his report until the next day so he decided to take the afternoon off and go fishing.Is this sentence acceptable?

No.
It needs some improvement; it's my take on it:

Steve needn't finish his report so he's decided to go fishing in the afternoon.

AnonymousNo.It needs some improvement; it's my take on it:Steve needn't finish his report so he's decided to go fishing in the afternoon.

This changes the tense though. Preserving the original intention.

Steve didn't need to finish his report until the next day, so he decided to take the afternoon off and go fishing.

Thanks for your replies.

What if I want to say that Steve did finish his report before the deadline, even though it wasn't necessary, that's why he took an afternoon off to go fishing? Was "needn't have finished" impossible to use in this case?

There was actually the option between needn't have and didn't need to, but I didn't find the sentence clear, so I'm asking.

AnonymousWhat if I want to say that Steve did finish his report before the deadline, even though it wasn't necessary, that's why he took an afternoon off to go fishing? Was "needn't have finished" impossible to use in this case?

The needn't have suggests not only that there was no need but the fact that he did finish it was somehow a waste. It would be