I think you misread the PC cost.
It's $1600.
or $3200 for 6 Mh/s
Or $500 for an additional 3 Mh/s
In other words even with the 13% lost profits from the additional power requirements 2 PC units would bring in about 40% more profit for a 15% base cost increase.
Not a good buy, and that's before considering non mining resale value.
Then as I pointed out before, perhaps the people that do not need to save money on electricity would like to be directed to an operation more to their liking.
http://alpha-t.net I am sure their products will meet your requirements.
The chances of someone even with the technical know how prefering to run and manage that many PCs will enjoy themselves in the process. They are not our target market anyway.
Side note: all the calculations were based on 0.10$kwh