I am 10 months older than my wife. Her SS benefits are larger than mine, so I filed for retirement at full retirement age, and she began receiving spousal benefits. Last November at the age of 70 when she filed for benefits on her own account, I planned to change to spousal benefits on her account. But we were told by the SS representative that I could not. My increase would have been over $100/month. Is what the SS rep told me correct? Thank you.