All - I just got finished booking a companion pass award (open jaw) over the phone in First and the taxes quoted were about $275 more than what was showing online. Unfortunately it's not possible to book an open jaw using a companion pass online - so it doesn't appear I had any options. The phone rep said sometimes the online system doesn't charge for all taxes, but couldn't elaborate. Think it's worth calling back to see if they will refund the difference or am I out of luck? Is this commonly known? As an aside - it took about 50 minutes to complete the reservation as they were having all sorts of computer issues. Fun.