I decant my 9 kg bottle into the 4.5, 3, 2 and 1 kg bottle's before refilling the 9 kg bottle. Gone are the days of weighing bottles and paying for what you get. If I take a half full 9 kg bottle in for filling, I get charged for filling an empty bottle. However the price for filling a 4.5 kg bottle is more than half the cost for filling a 9 kg bottle!$@#$!#
My bottles are still within testing dates.
I took a swap and go bottle that I had at one point in time to Mitre 10 for refilling, and was told they wouldn't fill it as it was out of date.
There seems to be a concerted effort on the part of refilling locations to gouge on prices for refilling. In Adelaide now you will not get any change out of $30 for a swap and go type bottle swap over, surely it must have scales of economies to make it cheaper to swap over, rather than taking someone away from the till at the petrol station to fill your bottle for you. And Mitre 10 are not far behind with refilling a 9 kg bottle, $25 dollars the last time I went there.
My point here is, regardless of whether it is illegal or not to fill my own bottles, I will, using common sense, continue to decant my own bottles. I am not in the habit of giving money away to greedy parties who do not have my best interests in mind.