Tipping Talk

My husband and I are on vacation in Los Angeles and had a date night last night. We went to a fabulous Mario Batali restaurant in West Hollywood called Osteria Mozza and had an amazing meal. We had the sommelier help us select an incredible Barbera from "the Barbera King", Bricco dell Uccellone (I highly recommend it!). When the bill arrived, we had the same debate we always have after a wine splurge... what and how do we tip? I was a waitress so I generally tip between 18 and 20 percent, based off the final price (not before tax or without alcohol). I will tip less for really poor service although I can't remember giving less than 15% unless it was a disaster, even then I leave something (it's the poor college student waitress in me!). So my thoughts were that we tip on the final price and I assume (and hope) that the waiter passes off the sommelier's portion of the tip. I was curious what the proper etiquette is so I did a little google search and found this from Peggy Post (via the Good Housekeeping site):

Q: At a dinner out with friends, we ordered an expensive bottle of chardonnay. When the bill came, they insisted that we didn't need to include the cost of the wine when calculating the tip, only the food. Is this true?

A: Your waiter is entitled to a tip based on the cost of the meal and the alcohol. The exception: When a wine steward, or sommelier, selects a bottle and serves you. If so, the wine expert is given a separate gratuity of 15 percent to 20 percent (depending on the service, as well as the price and number of bottles ordered), and your waiter should be tipped only on the food portion of the tab. Customers usually hand a wine steward cash at the end of the meal (he should come to the table when you're done), but if you want to pay for everything by credit card, look for an extra line on the bill just for the wine tip.

I have never seen an extra line on the bill for the sommelier's tip so I suppose it would be nice to denote it somewhere or give him cash as suggested so he, or she (although I have never seen a female sommelier - have you?), receives their full portion. So what do you think about all this? And what do you think you do if you pick out your own bottle? Do you still give the same amount of tip for the wine (for the waiter)?

And speaking of ... if you've ever wondered about the proper way to pronounce it (as we once did), it's [suhm-uhl-yey].