Ambiguity of "might have/could have"

Question

The following is taken from PEU¹ 339.8:

May/might have ... can sometimes refer to the present or future.

#1 I'll try phoning him, but he may have gone out by now.

#2 By the end of this year I might have saved some money.

For #2, I think it would create ambiguity without context:

It could refer to my expectation that I am likely to have saved some money by the end of this year. I think this is what it's intended to mean here.

But it could also stand for a hypothetical situation where it would have been possible for me to save some money by the end of this year if I hadn't spent a lot on my new Audi.

Is my understanding correct?

If my understanding is correct, then is it possible to substitute could have for might have with meaning unchanged?

#3 By the end of this year I could have saved some money.

Is #3 also ambiguous without context? It could refer to an attainable expectation or a possibilty that will not be able to come true.

Or, to put it another way, can could have be used to express factual possibility without time restraints just like might/may have in #1 and #2, both meaning "by the end of this year I will possibly have saved some money."?

^{1. PEU = Michael Swan's, Practical English Usage.}

Answer 1

I do not think that #2 is ambiguous without context. It means the first thing that you suggested.

You could make that sentence mean the hypothetical situation that you mentioned, but that would require context. With no context, though, nobody would think it meant that.

The same is true of your sentence #3. Without context, it means simply that it is possible that when the year is over, you will have saved some money. You could add context, though, to change the meaning to your other interpretation.

Answer 2

I strongly disagree with Daniel's answer.

No.2 is ambiguous. Of course context gets rid of ambiguity. That is the whole point. I agree that the two possible readings of expectation and hypothetical are both good here.
Maybe one is less common, but you can't just say that because one meaning is less obvious or wouldn't be used as much that it is not an an ambiguous sentence.
There is ambiguity because the sentence could be interpreted two ways, and to distinguish them you would need context. Modals are often ambiguous in this way, and the only way to clear these things up are context. If that sentence was taken out of context, you may think it means one thing and wouldn't think of the other... but if you were asked "is this ambiguous?" you should be able to see the possibility for ambiguity there and create a context in your head where a second meaning might arise. If this cannot be done, there is no ambiguity.