The modifiers to the right of the serve ratings apply to the opponents' return ratings for that serve. The serve ratings themselves don't change unless you roll on the Event Chart.
The serve ratings are basically one sequence of numbers. In the rulebook, David Ferrer on Grass is 0-5 WIN, 6-73 1st Serve, 74-99 2nd Serve. So, let's say he's the favorite and rolls on the Event Chart, Favorite. Here he rolls a 5: 2nd Serve +5. His 2nd Serve rating changes to 79-99 (meaning the 1st Serve is now 6-78).
