Social Security increase and Obama Care

I just signed up for Obama Care and I'm waiting for my first bill to arrive in the mail so I can pay my first premium payment by December 31st as instructed.
I just received in the mail a notice from Social Security announcing that my Social Security will be increasing by 2% for 2018 and it suddenly occurred to me....My gosh, I have not even paid my first premium payment for my 2018 Obama care and already I have to go back into the market place to readjust my household income as required by the Market Place in order to correctly figure my subsidy for Obama Care.
My question is.....Do I really need to update my Obama Care information concerning this 2% increase in Social Security, or did the Federal Govt. already take this increase into consideration when setting our subsidy amout for 2018. Surely the Federal Govt. knew about this 2% increase and I would think they would have taken it into consideration when setting our subsidy amounts.
It would be completely ridiculous for folks to have to go back into the market place and update their household income all over again when we have not even received our first bill for our first premium yet.