Apologies, if I mis-spelled either of the two words, as I'm not sitting next to my books or dictionaries. So... are these two separate items on the restaurant bill? My wife insisted that, if there was already a coperto ("cover charge"), then we shouldn't worry about a tip. Sometimes this was 3 euro per person, and I have a hard time thinking that's just for the basket of bread they bring to the table. On the itemized bill, we could see coperto listed, but no mention of "servizio incl" or "servizio not incl." Rick's book was a little vague on this subject.
Coperto is "cover charge". This is what they are charging you for sitting at the table. It is usually a couple of Euros. Servicio is the "tip" for your waiter.
The "coperto" is for the bread and table, and maybe water (you can get non-bottled water in many places if you ask for it). This does not go to the staff - most wait staff (in decent restaurants and cities) are paid by the hour and have a contract.
Italians for the most part do not tip at restaurants. It is always welcome though by the person serving you. Only a few restaurants actually have "servizio incl" or "servizio not incl" printed anywhere on their checks or menus.
I have gone from a 20% tipper to usually not tipping after 5 years living here. We almost never tip at lunch, and not all the time at dinner either - depends on the place - but only 5 to 10%. This is normal here.
However - don't think you are tipping because you pay the "coperto"! If you enjoyed your meal and you tip back home, then tip in Italy - the staff will appreciate it.