I can't comment on the specific sums you've mentioned, but I'm sure you've done your sums OK! I'm also sure that you'll get many who'll tell you how you could do it cheaper or better. Anyway, it's your decision where you go and what you spend.
You've made no mention of flight/study equipment. I'm thinking of DR computer (CRP5 to some), calculator, headset (many like to have their own), kneeboard etc, etc. I assume you're trying to work out your total budget for this period, so you really ought to add some for entertainment - you'll need it! - clothes, transport etc.
I'm sure you'll get more suggestions!