Settlement typically means the transaction has "gone thru" or occured. It's a term indicating a form of escrow. In crypto, it most likely means the price at which the blockchain has last verified price; whereas, in yellow might be the price bitshares last traded (without full settlement by the blockchain). Is BitShares blockchain having trouble keeping up with all the transactions? Or do you get this screen ALL the time?
Settlement price might also include mining fees and other commissions.
Whereas "last" traded price does not include such fees, and is posted so people know what BTS price is.
Really wish we understood it more, the margin call price makes no sense to us, unless they mean this is the price at which newest trades are occuring which haven't settled on the blockchain. margin calls are what brokers use to back up a user's account with funds. So if you borrowed money to buy bitshares, a margin call means the brokerage doesn't think you have enough bitshares in your account to cover losses.
For example:
If you have $1,000 in your account, but borrow another $9,000 to buy $10,000 worth of stock/bitshares, a 10% drop in price would wipe out your equity. In volatile markets like today that could happen in seconds. In this case, the broker might set up a price for which you'd HAVE to sell your position, a "margin call price" such that your account would have more USD to support your holding a declining Bitshares price. All this assuming you've borrowed, have you?
We don't KNOW the answers you're searching, but hope anything we wrote is helpful.
Somebody knows. Hoping we get a taker.
Send your request to @stan