I understand you not wanting to give Apple 30% compared to keeping it all going through your own store but I'm fed up managing licenses for software that I've bought from individual developers (I have a license for AudioHijackPro and I can no longer find..).

I was about to buy Fission just because it was on sale but I see that the MAS version is still full price. Sometimes getting 70% of a discounted price is better than 0% of full price.