Present perfect or not?

Question

I have some sentences that I wanted to ask the experts here.

When emailing people in present tense, do I have to use future tense in order to be grammatically correct?

"You need to call me whenever you receive my parcels, because that is the only way for me to find out if my parcels have been received."

Should this be:

"You need to call me whenever you receive my parcels, because that will be the only way for me to find out if my parcels are received."

or

"You need to call me whenever you receive my parcels, because that will be the only way for me to find out if my parcels have been received."

On the sentence below, I'm not sure if I should construct it with present perfect.

"Sometimes, I find that I've done something I shouldn't have done."

Should it be:

"Sometimes, I find that I did something I shouldn't have done."

The one below, I actually read it in a book.

"I'm sorry, you shouldn't have to see that"

Is this some kind of present tense sentence? I think is should be "you shouldn't have seen that", but since I read this in a book, it must be correct.

Please help!

Answer 1

For your first example, I would prefer your first form of the sentence, although you could also probably say,

"You need to call me whenever you receive my parcels, because that is the only way for me to find out when my parcels are received."

For the second example, both sentences are gramatical with subtly different meanings. For the meaning that I am assuming you are intending, you should use your first sentence.

For example #3, "You shouldn't have to see that" is a sympathetic statement, while, "You should not have seen that" is more of a matter-of-fact statement.