A cost question about PoS-2020

[LuozhuZhang]

ASIC-based proof of work

Total cost of attack: $486.67 (ASICs) + $0.08 (electricity+maintenance) = $486.75

I don't understand how the 486.67 and 0.08 are calculated here 👇

1. I understand 1$ block reward per day, miners are willing to pay up to 1$

2. According to the average, 1/3 of the cost of ASIC-PoW is electricity + maintenance (0.33$), and 2/3 of the cost is the machine (0.67$, as capital lockup cost).

3. So without considering the polyline, I understand that the capital cost should be 0.67 * 365 * 2 = 489.1

4. And I need to pay for electricity and maintenance for the day (0.33$)

So I don't understand how $486.67 + $0.08 is calculated, can you give me some hints