If you're actually going to put in numbers for vertical, they shouldn't be guesses. Use your cell phone's memo feature to record what lifts you use, like "111113" might be 5 runs on the quad, and 1 run on the main street lift, and you can add them up aftewards....
or, if you have a data plan on your cell phone like I do, I'm writing a super-low-bandwidth-using live updater of your stats, so someone could watch you ski runs in real time