You appear to be using an old version of the handbook. The current version is the most authoritative source. In it, they updated the verbiage. If your quote comes from the (ISC)² webpage or other document, I recommend sending a reference email@example.com so that they can update it. I have done this a few times now. They are very receptive to constructive comments.
...CPE rollover credits are limited to the number of recommended annual CPEs each year for that credential, and must be earned within the last six months of the three-year certification cycle....
(page 11, with the suggested annual totals being found on page 5).