After reading this board and some other sources, I currently plan as follows:
(1) spouse takes SS on her record at 62;
(2) spouse switches to higher spousal benefit at her full retirement age when the spousal benefit is maxed out;
(3) I'll wait until 70 to draw SS.
I thought this approach looked like a winner ... until I contacted SS.
Their comments regarding spouse taking an early benefit based on her work history followed by a step up in the benefit at her FRA were:
THERE IS NO STEP UP.
Your wife's benefit, whenever she starts the benefit stream, will be based on the larger of the two work records - hers and yours. If she starts before her full retirement age, there will be a reduction from that maximum benefit which will apply for all of her benefits until you pass away.
If she starts her benefit stream at age 62, she will receive 37% of her maximum benefit available based on the larger of her work history or your work history.
When you pass away, (assuming that your work history record is larger than hers), she will continue to get the benefit that you were getting at the time of your death or the benefit that you would have been eligible to get.