Joining the thread late so apologies if I missed something above that makes my answer not make sense...Originally Posted by Helen B
The above results are what I would expect, the spot meter reading of the highlights is about 2.5 stops over the incident reading. The incident meter is giving you the middle of the assumed 5 stop range (so, zone 5-ish) the spot meter of the wet pavement is giving you a highlight reading (zone 7-8 or so) about 2.5 stops above the average.
The spot meter is trying to tell you how bright the thing you're pointing it at is. The incident is trying to tell you how strong the lighting its in is. Similar ideas but different enough for 2.5 stops.