Contract work while on JobSeeker - will 50% upfront payment screw me over?

Hey all, hoping someone's been in a similar situation and can help.

My situation:

- Currently on JobSeeker ($1,008.70/fortnight including supplements)

- Just landed a contract for a project worth $20k in total

- I have an ABN and it's a proper contractor agreement

Contract runs from now until end of November

The dilemma:

The client is offering me two payment options:

50% upfront ($10k), 50% on completion
OR
Regular fortnightly/monthly invoicing

I'm worried that if I take the 50% upfront, Centrelink will see that $10,140 hit my bank account and cancel my payment for that fortnight (or worse, multiple fortnights).

What I've investigated so far:

Centrelink supposedly "annualizes" self-employment income (spreading it across the year)

BUT their website also mentions lump sums can be assessed differently

Can't get a straight answer from anyone?

My questions:

Has anyone received a large contractor payment while on JobSeeker? What happened?

Should I play it safe and invoice fortnightly instead?

Does having an ABN actually make a difference here?

Any experiences or advice would be massively appreciated. Calling Centrelink tomorrow but we all know how helpful they can be... 😅

EDIT: Yes, I'll declare everything properly. Just trying to understand the rules before I decide on payment structure.