How do I model SS ex-spousal benefits with future marriage after age 66?

My domestic partner of 17 years and I both filed for divorced ex-spousal Social Security benefits this year. Hers is $1,113/month. Mine will be around $800/month. We are both 66 years old and plan to switch to our own 32% higher Social Security retirement benefits when each of us turns 70 in 2020. I am retired and receiving a small pension and doing Roth conversions, while she is still working full time and intends to work through at least 2017, possibly longer. I have another small pension that I have not signed up for yet that grows by 10%/year delayed retirement credits.

Social Security Ex-Spousal Benefits 66-70

Both my domestic partner of 16 years and I plan to take our respective Social Security Divorcee Ex-Spousal Benefits starting this year from age 66-70 while letting our own retirement benefits grow 8% a year until age 70. I entered this into the annuity section as an a guaranteed annuity for 4 years. However, it seems to put each annuity in for the entire year rather than by age as the Social Security section does (which creates partial year amounts depending on birthday month).