have you used the spreadsheets provided in the link? I tried using the rating puf and the SLCSP amount did not leap out at me for any policies in any county.
The one time I had to obtain this number (multiple 1095-A forms received), I had to actually go partially through the sign-up process for my state (which does not rely on the federal exchange). The number you are looking for does not seem to be widely published anywhere.
In my response to the IRS letter, I wrote "The amount shown for SLCSP premium on Form 8962 has been verified at CoveredCA.com." This seemed to work.
I tried to go through the sign up process as well, and anywhere else I could for my account in the interests of guiding the client to his SLCSP; but I cannot get to a 2019 figure; only 2018.