the equation is correct but have no idea where from you have this values and how long will you wait. Plus I don't believe you can actually buy Prime1 miner new and not second-hand from any one else than One Stop.
Prime1 miner = A1 clone, same as Dragon, its not based on the Antminer S2
From your web site: "Chip: ASIC A1 28NM, 4 modules, each with 8 chips", Antminer uses a completely different ASIC
This is just the same as all other A1 clone resellers on this forum, delivery from them is 3 days from stock for $1780
So its the same just $500 more expensive.
Just wondering if you realised, might be why your thread is so quiet.