Each stay is 180 days at a time - it's a five year multiple entry visa but for up to 180 days each stay (you can just border run every 180 days). You should just put anything up to 179 days in that section to be safe.
Congrats! I will be applying through Sydney sometime in the next week or so. Good to know the processing time for yours.
Did you send all pages of your four months of bank statements? I have had more than the required 500,000 BHT for a long time, and I'm happy to send them all of the statements from the past six or so months but it will be over 30 pages with all the transactions listed π± So I'm not sure if I could just send the closing balances for each month.