kannst du

Weisst du zufaellig auch ob das richtig ist (einkommensverhaeltnisse)
Income levels:
Please list all incomes within 12 month before date of duty of payment (Duty of payment starts in general 6 weeks before due date/birth date. The duty of payment starts already 4 months before date of birth/due date if the mother of the child isnt able to be gainfully employed or get employement as a result of the pregnancy.)

I would simply call it "Income."

Please list all sources of income with in a 12-month period prior to ...

Maybe; I'm not sure what you mean by "duty of payment." Zahlungspflicht?

Also: is all this supposed to be BE or AE? There could be quite a difference.

It's difficult to know with your long construction what you are trying to say without the original German.

"within" doesn't sound right to me.

Maybe: Please list all sources of income during the 12 months preceding the date of begin of payment obligation ...

Again, it's hard to tell.

Please list all sources of income within 12 months before the benefits* are due to start. Benefits generally start 6 weeks before the due date. If the mother is not able to gain employment or remain in employment as a result of the pregnancy, benefits already start 4 months before the due date.

*perhaps - depending on what kind of payment this is.

"unterhalt"?
thanks

benefits for child alimony is wrong.

There is alimony and there is child support, and they are two different things. Neither is a benefit.

"unterhalt"?
thanks

Deutsch heisst es: "Die Unterhaltspflicht beginnt regelmäßig sechs Wochen vor dem voraussichtlichen Geburtstermin. Falls die Kindesmutter infolge der Schwangerschaft an einer (bereits ausgeübten oder geplanten) Erwerbstätigkeit gehindert ist, beginnt die Unterhaltspflicht sogar schon vier Monate vor dem Geburtstermin."

Please list all income within the twelve-month period prior to date of payment obligation. (The requirement to make support payments normally begins six weeks before the anticipated date of birth. If because of pregnancy the child's mother cannot work at her regular job or obtain other employment, the payment obligation may commence four months before the anticipated date of birth.)

NB: income ("Betrag") und sources of income ("Arbeitsgeber") sind auch zwei verschiedene Sachen.