The fare in coach
The exact same itinerary in "H" class 10 Mar, VN317 HAN-DAD and 16 Mar, VN325 DAD-SGN came to 1659000 dong if one bought it directly from VN. $1 US is presently 16000 dong.
Each of our tickets cost $134 US + 3% credit card fee from a company called TMK Travel in Saigon. This came to more than 35% premium for the travel agency. I will no longer use a travel agency for tickets. Instead I will buy them in country from VN or have the hotel conceirge arrange for them.
It has already been mentioned that at least for the DAD-SGN segment food is exactly the same in J as in Y so the difference is the seat size and pitch as well as the lounge access.