There are no point modifiers associated with each scoring category in Rotisserie or Head-to-Head leagues.
Each home run, stolen base, win, save, etc. is added as one unit to your season or weekly totals.
In a Rotisserie league, you earn points based on how you rank in each scoring category in your league. In Head-to-Head leagues, you earn wins and losses based on how your weekly totals measure up against your opponent's in each category.
Points-based Head-to-Head scoring (similar to fantasy football scoring) is available, but only in Yahoo! Sports Fantasy Baseball PLUS leagues.
The Yahoo! Sports Fantasy Baseball PLUS help page features a list of features that are exclusive to PLUS leagues.