Mixed tenses in example

Question

I am trying to sort out the tenses in the following example from above:

Dejó el trabajo porque quería mejor sueldo.He left his job because he wanted a better salary.
The first verb (dejó) is preterito indefinido indicating a complete action in the past.
The second (quería) is preterito imperfecto.

I think this is because "he" probably had been wanting a better salary for a while before he left his job and it was an ongoing action. Is this the right way to think about this sentence?

Answer

This could be because leaving his job is a completed action, hence triggers the indefinido, whereas the "wanting a higher salary" is a background description in the past, which usually triggers the imperfect. Someone more clever than me will no doubt come and rescue my explanation.