That is a tiny increase, no problem at all. Once BFL starts shipping, if they ever do, I'd expect to see difficulty double for a few adjustments in a row. Those will be interesting days.
Actually Avalon ASIC has already two more shipments incoming, so difficulty is virtually guaranteed to go up by 40 TH/s when those hit, even if BFL never produces anything. Also, look at how many people are buying up GPUs or turning on their GPUs trying to GPU mine these days. Some have shifted over to Litecoin because it is more profitable than mining on Bitcoin, but there's a jump in hashing power at both places that can't be explained by ASICs alone, thus it's likely coming from GPUs. If BFL ever makes ASICs and mines for itself -or- if it ships out to customers, I'd expect difficulty to double for several adjustments in a row as well.
P.S. Every increase in difficulty hurts, no matter how "tiny," and I don't think 12% is tiny unless you are comparing it to the ASIC difficulty rise in March. A 12% increase in difficulty means a greater than 12% decrease in net profit if you pay more than zero for electricity. For instance if you were making $11 - $4 electricity = $7 profit, and it goes down to $9.68 - $4 electricity = $5.68 profit, your profit went from $7 to $5.68, which is a drop of 19% in profit even though revenue dropped "only" 12%. These are just example numbers of course, to illustrate the point that profits drop faster than revenue for anyone paying more than zero for electricity.