Complex sentence: Benefit payments starting at ages other than 65 are adjusted actuarially, which means the maximum guaranteed benefit is lower for those who retire early or when there is a benefit for a survivor, and higher for those who retire after age 65.
Split into simpler sentences: Benefit payments starting at ages other than 65 are adjusted actuarially, which means the maximum guaranteed benefit is lower for those who retire early or when there is a benefit for a survivor. Likewise, the maximum guaranteed benefit is higher for those who retire after age 65.