OK, so you started collecting in 2008 at the age of 62. This means that you opted for a reduced amount on your own record, but if it was your own record amount, it means that your own amount was preferrable to a spousal amount (which would only have been about 35% of his full amount.)
Now, once he died, since you were married more than 10 years before you divorced, and because you were OVER your full retirement age, you'd be eligible for a divorced WIDOW benefit of 100% of his primary insurance amount. It sounds like that is what you got in or around 12/2015. Let me know if you have reason to believe otherwise. Now, usually that means if his amount was 1700, and you were already getting 700, they make up the difference to get you to that widow amount of 1700. So that would be your 700 plus 1000 widow addition for the total of 1700. So, assuming those numbers to be accurate, the question then is, why the $400 drop? And I believe you are saying the SSA did not send you a letter of explanation. So, let me ask you a few more questions. If these end up resulting in no expected drop, then it could be that the SSA made a huge mistake.
OK: In 2013, 2014, 2015 did you experience a big increase in income? Such as sale of a home, cashing out a big retirement benefict or investment? Anything?
Also, did you recently change your Medicare Supp plan or Advantage Plan or RX plan?
I look forward to your answers to these 2 questions.
No, I don't need any info about is military life or demise, as it does not effect your SS eligibilities.