Let's try another way of doing the math
S17E > 45w/th
M20s > 48w/th
3w per TH difference, let's take a medium scale farm with say 1000th , that is 3kwh difference, say you pay 6 cents per kwh , that is about 130$ a month or 1560$ a year ( not that big of a deal to be honest
)
now let's price difference, the M20s 64th sells for 3200$ in China (from resellers) with "early September shipping" , now let's speculate on what bases would anyone want to pay more for the S17E provided it ships around the same period.
M20s > 47$ per TH
S17e > if 47$ per TH that means it will sell for 3011$ ( unlikely)
let's assume they will sell it for 3500$ , or 54$ per TH , that is 448$ more for 64 th > ((54$-47$) * 64th) in order to save 64*3w = 192wh , or 8$ per month if you pay 6 cents per kw , so you will need 56 months to ROI the price difference ! that does not make any sense to be honest
for those who pay more than just 6 cents per kw, it makes more sense to pay even more than just 3.5k , for large players 3w less per TH is a lot of money saved , if it takes 3 or 6 months to get back the price difference that should not be a problem to most people.
but let's wait and see what price will they ask for.