I know that in time clauses we can often use the present perfect instead of the present simple to indicate the completion of an action. However, I have some doubts sometimes.
I wrote down the following examples of future time clauses in which, according to the answer key, the present simple is used. I wonder if the present perfect will also work in these cases?
1. I won't buy you a cake if you don't behave yourself.
=> I won't buy you a cake unless you behave yourself.
2. Jack is seeing the doctor tomorrow. He will be all right.
=> Soon after Jack sees the doctor, he will be all right.
3. I will arrive at my office at 8 o'clock. I will do it immediately.
=> The moment I arrive at my office, I will do it.
4. I'll let you know when the party starts.
5. I won't speak to him unless he apologises to me for being so rude.

Thank you for your answer. While we are on the topic of future time clauses, I'd like to ask you about the following sentence: Call me when you do your homework, so I'll help you.
Is this sentence correct grammatically? Or it must be: Call me when you are doing your homework, so I'll help you.

Oh yes. It definitely should be "and I'll help you". I just didn't take notice of that part.

I thought the first sentence was fine, as you said. One teacher, however, claims it is not and only "are doing" works here. That's why I was a bit confused.

I am not sure if I fully understood your post. By saying "event", you mean "doing the homework"? And the last sentence is quite unclear to me. Could you please explain it to me once again?

"Call me when X" could mean before, during or after X. In this case, pragmatically/contextually it is most likely before, because you would want help starting at the beginning and then continuing during. Alternatively it might mean during, when it becomes difficult, or maybe after, to go over the answers to see if they're correct. But most simply, I'd assume it means before, which technically isn't part of the event itself, so it's a bit odd grammatically.

You are talking about the sentence "Call me when you DO your homework", which can be interpreted in three ways. Is that right?

Now I understand.

Actually, I'd say the first sentence is a default, and the second would only be used when you want to emphasize 'during'. More naturally, the second would be used to refer to the beginning of the event, assuming you want help throughout. It's actually slightly odd grammatically in that the event may have not yet begun, but close enough contextually.

In the second sentence you said "the second would be used..." You probably meant the first sentence, i.e. the one with the present simple? That's why I got confused.

That's OK. Thank you for your explanation.

Yes, you can emphasize completion. Sometimes it's awkward, though, as in (3) and (4) there.

The emphasis on completion seems to conflict with the uncertainty or "make a decision" sense of some of those, like (4), which in the present would mean "If I change my job, I should first tell my boss", but with the perfective suggests something like "I've already decided to change, but I should now tell my boss before it actually happens" (confusing).