I do factor in specials that are available at the time that I run the calculations and I post any discount codes on my website.
The higher (apparent) profitability of UMISOO and AntS2's is because of their much lower $price. The payouts are smaller, but the $price per GH/s is proportionally even smaller, making the payout a higher percentage of the $price.
The price to payout ratio is higher because they are a higher risk. They return more negative blocks than the AntS4's and AntS5's and they will go completely negative sooner. To compare risk, look at the fee% column. The higher the fee percentage, the higher the risk of getting negative returns if BTC drops or difficulty sky-rockets.
Thanks for your questions.