Either my post wasn't clear or ppl aren't reading it properly.
The $400k refers to monthly costs of an operation that mines 150 x 25 BTC in that period i.e. ~$1.5m @ $420, or a net profit of >$1m per month.
Re: halving, yes I can divide by two too.
ok so 400k in operating costs. and they make 1M per month. meaning they wont sell for less than that most likely double. so you are looking at a 2M expense. Again the same logic applies buy 2M worth of bitcoin and sit on it. Depending on how active you want to be for 2M worth of coin you could buy it and flip it daily and make a nice size profit.
more then likely the mine wont sell/be bought because they themselves know how much they are making and that 1M a month they are making now they could wait till 1/2ing and sell and it make more money than what you were offering.