Yes, I think that was a perfect answer. I will just assume that the stock doesn't decline for the example. Sometimes it might go up, sometimes down. I think if a sold call is exercised and I don't own any shares, I would be in a short stock position and not long?
Hm! I botched that! Good catch. -- Since I do not do this, it is not clear to me if your Broker would deliver the shares to the CALL holder and just charge you for the difference over your short CALL option strike, or if they would allow you to take action. -- This is not my area of competency. If you are looking for Margin instead of MAX Risk, the following may be of value (from TDA). "https://www.tdameritrade.com/retail-en_us/resources/pdf/AMTD086.pdf"
That is interesting, I wondered that too if the broker just would charge the difference over the short CALL option strike and current stock price. It seems logical but perheps I will need to ask them. I could find the above text in the PDF. It seems interesting as it also seems to take not only liquied cash in the account as security for a loan but also possible shares which has a value.