Hi there
you are still eligible for B if you earn under a certain amount (i think is is around $22K???? DONT quote me on that amt).

If you are on a guaranteed wage then they will be able to calculate your rate.

Both will be reduced. as A goes off your combined income.

We overestimate our yearly earnings (as i am casual and work varies) and then get lump sum refunds at tax time if it is under the estimate.

you can type it in online to test how much you will get from centrelink too (estimated) if you are trying to work out the work life balance