I passed SA6 in Oct 2010 at the third turn. I had hoped to clear in the first, but wrote more than I should have that time. In the second, there was a cardinal error - I just couldn't get what stagflation exactly meant!
Also, I feel if you are not in the thick of action in a developed country market, there's a slight disadvantage - at some stage of the writing, you would be exposed. I assume you are from the UK, and have been reading on topical issues i.e. macroeconomics, LDI, pension buyouts, etc.
There's only a thin line between a pass and fail grade. It makes sense to continue SA6 than switch to SA5 just because the SA5 results were relatively better this diet. Indeed 13% is a dampener, but I guess the law of averages would catch up!