On many attractions when you return, you still wait for 20 to 30 minutes, especially if you need a transfer vehicle. So, in your example above guest B would have a total wait time of 70 to 80 minutes. Sometimes you get lucky and get right on, but it is highly unusual for the wait when you return to be less than 10 minutes and is often longer than that.....but you absolutely can and do wait longer at certain attractions, especially if you need a transfer or accessible vehicle.How exactly does the das make you wait longer? The das time is stand by minus 10 minutes. So, guest A is in stand by for 60 minutes. Guest B with das is using a scheduled fast pass, or getting a snack while waiting their 50 minutes. Both ride after the standby wait time. But, guest B has not spent 60 minutes just waiting on line.
There is simply no way to make the experience the same for all guests, but in no way is the das guest having a longer wait to experience rides.