The thing is, eBay.com.au actually admit that they make mistakes in their policies. For example: "This increase has become necessary as the fee changes made earlier this year (most of which were reductions), incentivised more sellers than expected"

I don't buy that line for a second. They knew a few months ago when they made the changes that they would be increasing the subscription fees.
I knew it was too good to be true. It makes sense to make the jump from ten bucks a month to 50 bucks as painless as possible.