"Until" followed by past perfect or past simple

Recently we have been learning tense sequence with using after, before and so on. One of them - until turned out troublesome for me.

My first exercise was to write this sentence with until: not to agreed to take Kevin + they see how well we get on.

Logic says to me that not to let was the first action and seeing was the second action.

They hadn't agreed to take Kevin until they saw how well we get on.

My teacher told me English sometimes wasn't mathematical and logical and this sentence should sound like that:

They didn't agree to take Kevin until they had seen how well we get on.

I said to myself: " Ok. After until it should be past perfect (simple or continuous)"

The second exercise: She didn't watch television. They bagan to broadcast signed TV programmes. (use until)

I wrote this sentence accoring to my rule After until we use past perfect!

She didn't watch television until they had begun to broadcast signed TV programmes.

According to my teacher this was wrong and this sounds better:

She hadn't watched television until they began to broadcast signed TV programmes.

It is the first time I have been shocked so much by English. Who knows and has time to explain?

Trying to tap into your teacher's mind:

It seems that your teacher wants you to decide how the events in the sentence are arranged chronologically and to use past perfect for the event that happened further in the past or before the other one. Let's check this hypothesis!

• Example 1:

not to agreed to take Kevin + they see how well we get on

They want to see how well we get on before they agree to take Kevin. So we have:

First they see how well we get on -> previous event -> past perfect (had seen)

Second/after that they (may or may not) agree to take Kevin ->later event -> past simple (didn't agree)

The result:

They didn't agree to take Kevin until they had seen how well we get on.

• Example 2:

She didn't watch television. They bagan to broadcast signed TV programmes.

At first She didn't watch television. -> previous event/circumstances -> past perfect (hadn't watched) Later They began to broadcast signed TV programmes. -> later event -> past simple (began to broadcast)

The result:

She hadn't watched television until they began to broadcast signed TV programmes.

It works!!!

I agree with the comments that: many variations (including the ones where both clauses are in the same, e.g. past simple, tense) are correct; until doesn't have to be restricted to past events (and you can even preserve the logic followed in this post - as in Andrew Leach's example: They will not let me take Kevin until they see how well we get on.).