Subject: Re: More cash-secured put arithmetic
You can generally trade wide-spread Berkshire options at 25% up the spread or better, and you can pretty much count on doing it at 30% of the way across the spread.

So, you could generally sell this contract at .25*221.70 + .75*224.70 = $223.95

I think you have the .25 and .75 swapped. When selling, the achieved price will be closer to the bid than the ask.

But I was giving a worst-case, to point out that the interest was the main source of reduction in the net price, versus the time-value, which is near zero. Either positive or negative.