Hmm, dunno if this will work but it doesn't hurt to try:
First try changing one CSC and leave it for lets say 24 hours and see what happens, you never know.
Second of all, try to disconnect your network (or turn the phone on without a sim or network turned on), then try with this changing CSC's, but also change the region on the phone to be corresponding to the CSC you are using, for example, if you use ATO, turn the region on your phone to Austria, if you use NEE, turn your phone region to Sweden, etc. (
see this post of mine how i solved the error i got when my ATIV S got the official update 8.1.1, my phone was and still is on NEE, so i changed the region to Sweden and i manage to pass the error and install the official update). See what happens.
I know this will take some time for you to testing, but my point here was to try all options before you flash any rom. As i see you already have many of the CSC's that got the official update, so if they didn't get it, chances they get it on the new room are none.
If you tried everything and still not on 8.1.1 then, go ahead and flash the rom. Wish you luck!