As far as = that

1. As far as I know, all my parking tickets have been paid, but I could be wrong.

2. It only lasted a couple of years, as far as I know.

3. As far as I am aware, no proper investigation has ever been carried out into the subject.

In all these three sentences above, can "that" be used instead of "as far as" like below?

4. That I know, all my parking tickets have been paid, but I could be wrong.

5. It only lasted a couple of years, that I know.

6. That I am aware, no proper investigation has ever been carried out into the subject.

I just found in a dictionary a definition of "that".

The dictionary explains "that" can mean "as far as", given the examples below.

A. No one knows anything about it, that I can find

B. He never read it, that I saw.

So I'm asking whether even sentences 4,5,6 are correct and "that" can be always interchangeable with "as far as"