Here's the pattern
for anyone who's interested.
All she is saying is that the total number of increase stitches you add for a v-neck is the same as it would be if you were doing a round neck -- in your case, the number is 18. If you were doing a round neck, you would have added 4 or 5 stitches on each side of the neck (18 times 0.25 to make what she calls the right front stitches and left front stitches), and then cast on the remaining 8 or 10 stitches in the middle (center front stitches). Since you're doing a V-neck, you will be increasing 9 stitches on each side of the neck every 4-6 rows instead of every other row (this makes the angle of the neck edge steeper), and join to start working in the round at the point
of the V -- you won't have any center front stitches to cast on at all since you don't want the neck to be rounded. Make sense?
If you happen to have Vogue Ultimate Knitting, a better explanation of the same basic pattern is in there. I've seen it in other books too, but lots of folks seem to have that one.