tenses

[azz]

Which of the following sentences is correct:

1. He worked here for ten years. He worked well.
2. He worked here for ten years. He was working well.

3. He was with our firm for ten years. During that period, he worked well.
4. He was with our firm for ten years. During that period, he was working well.

If in one or both cases, both tenses can be used, is there a difference in their meanings?

I don't know why I don't like 2 at all, but 4 doesn't sound wrong to me.

[Alan]

Certainly, the past progressive is strange without the specification of a period (as in #4). The simple past tense would do perfectly well, though, in either case.