Life is always a bit more complicated than you think. Setting configuration.setAllNodesUntyped(true) made a big difference to Q11, improving the run time from 13686ms to 10515ms, which is considerably better than the Saxon-B figure. But the run time for Q12 has increased, from 4296ms to 4837ms. Tantalizing. But before I can investigate any further, I'm off to hear Mozart's C Minor Mass at Reading Great Hall. That should take my mind off the problem if anything will.