Are you sure that the agent is incorrect ? It only looks like there is about $31.60 per person variation and that might be down to booking over the phone
Just checking on taxes for the journey, it looks like it is $918.41 per person , which would come to $1836.82 for 2. If being told that taxes are $1900 total, then this leaves a $63.18 variation or $31.59 each. How much is the offline booking charge?