Great job! I've carefully traced your calculations and could compare with my simple ROI results (investment 120 USD for 1 year):

        invest   fee     earn      ratio     revenue maint.  profit  \
BTC-HF     120   0.35    1.22777   0.731473  448.135 127.75  200.385   

         ROI, mo  percent  
BTC-HF   4.56667  166.988 

So, the most profitable now is BTC mining on HF with ROI about 4.6 months. In mid. July the situation was most profitable for LTC (pls see my post), but now LTC ROI decreased. New BTC price spike ($4300) dramatically change mining landscape.

I ponder to add mining difficulty and price estimation to my calc, but you have done it well. Followed!