i was going overseas some years ago on an extended trip and wanted to get the BAS done before I went and paid, as I would be coming back 2 weeks after the payment date. The way our business ran I was able to fill in and calculate moneys due from about the 15th onwards. This was pre being able to do it online, so I phoned up and asked if the form could be sent out a bit early. Had this entirely frustrating conversation which pretty much was no they couldn't send one out and in any case you couldn't fill it in that much before the end of the period. I then asked if I could have an extension so I could pay when I came back and it was no that wasn't allowed either get someone else to do it. When I explained that I was the only person in the business who could do it, she pretty much told me her parents were small busines people as well and they managed to cope so I should too! She told me to go away and be prepared to pay penalties!
Ironically the form actually turned up the day before we were due to leave, so all was well, but I was left amazed at how badly they treated someone who was just trying to do the right thing!