The only thing you are doing wrong is over analysing a kit wine!
Kit wines are not liike a scratch wine. Follow the instructions and let it work. I tell all my customers to do a step and walk away from it.
What you have on the top is just CO2. It will go away. If you are impatient, take the handle end of your spoon or paddle and break it up just like sticking your finger in the head on a beer to make the foam go away.
In addition, don't ever adjust the beginning S.G. or anything else of a wine kit, unless you like voidiing the manufacturers warranty. The starting S.G. can be off for a variety of reasons. The most common is not stirring enough. I have made over 120 batches without any problems, whatsoever. There are only 2 real reasons for taking the intial S.G. First, to make sure you stirred in the water well and second to make sure your kit is not bad. Unless you are way off on the S.G. 1.020 versus 1.070, your kit is fine. Remember, WE makes over 800,000 wine kits per year. I think they know what they are doing. Quit worrying about your kit wine and just make it and bottle it. It will be fine.