In reply to AlanLittle:
A part of that, I suspect, is the audience (and the flights, which do play a part!). It's entirely possible, I imagine, to climb grey slabs all winter long, whereas I believe the tufas can be wet in the spring. Your typical 8a.nu member is more likely to be cruising tufa 7s than grey slab 5s (they could of course do grey slab 7s, but why go to Kalymnos for that?) and so the logs skew accordingly.