1. UPSC does not awards average Marks. Yes I am sure now. In papers you have done well; you will get more marks than expected. In papers you havent done well; marks will certainly be less than expected. Same happened with me in Mains.
2. Being a Generalist is better. Surely UPSC searches for generalists. Given limited time and limited number of words, it is always better to write 5 points superficially rather than 2/3 points in details. Shoter questions in optionals from 600 words to 200 word types confirm this analysis.
3. Scaling is not accurate. Though everybody is only in a guess regarding scaling; still I will write a detailed post on scaling based on empirical studies. Till then I am assrting that there is no process called scaling in most optionals and certainly there is nothing like upscaling.
4. Moderation is surely done by UPSC. UPSC officially declares about moderation in between papers of same optional. Still inter medium moderation is not foolproof. There is evidence; a guy who wrote GS in Tamil language got 444 marks in UPSC-2007; marks which are above even exceptional. However other evidence suggests that moderation is largely followed correctly.