modal verbs - Ambiguity of "might have/could have"

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.}