In Mavericks the pinyin input method has changed slightly... better or worse? you decide.
Previously one could type pinyin for a character followed by a number for the tone -- this was an option that had to be selected in Preferences. That has disappeared. In its place, you now type pinyin and then, if you want, Option-Tab to cycle through the tones, whether or not they are available *for that pinyin* (if no possible character, the list is empty). So for example "hen" cycles through 4 tones and the 5th "cycle" shows the list of all characters regardless of tone (in case you forgot the tone). 噷, 痕, 很, 恨 are the first choices for the tones. This list is adaptive (as in older versions of the OS), your popular character come earlier in the list, if you chose "adjust word frequency" in the preferences.
So this change (1) can add keystrokes (if beyond the 1st tone) but (2) does not require a change to the preferences.