ok lets do some math
320exahash network today
190thash $3639 and 5.2kw per asic
=1684210 asics
=$6112000000 hardware / 105000 blocks* / 6.25btc
=$9313.52 per btc hardware cost
..
1684210 asics x 5.2kwh
=8757895 kw/h x $0.04
=$350315.7894736842 per hour / 6blocks** / 6.25
=$9341.75 per btc electric
total = $18,655.27 hardware+electric per btc for todays hashrate of 320exa
*2 years of blocks
** blocks per hour (even if you multiplied to the fortnight then divided by 2016 = same $ amount)
It doesn't take into account difficulty change, which may be very volatile.
difficulty does not change daily
but you can do some better math to show a different number at the next change. where you are measuring it out per day/fortnight
but at this periods difficulty and resultant of hashes. thats the math for TODAY
Your calculation is for today, but it would be very wrong to calculate earnings for the next 2 years and expect that hashrate/difficulty won't change.
So, difficulty/hashrate change should be taken into calculations.
Current calculation of the difficulty change may be not perfect, but I'm open for the ideas