I believe the listed value is based on a sliding window of the average price over a long time period, perhaps a week, of the exchange rate. Since the price rose dramatically in that time, it's taking a while for the value to adjust, but it's rising. If you want to know how much value you have, figure out the price of 1 STEEM on an exchange, and multiply the amount of STEEM (+STEEM POWER) in your account by that number, then add STEEM DOLLARS to the total.