Thanks for your reply! I saw Princess Website stated the following
"You may either obtain the visa on your own before your cruise, or a visa will be issued upon arrival in Vietnam. If you choose to have the visa issued on board, a visa fee of USD $56.00 per person (USD $76.00 per person for those participating on an overland package) will be charged to your stateroom account. If you obtain the visa on your own it cannot be an electronic visa (eVisa)."
Are they BS'ing or they really don't accept eVisa that I need to pay the overpriced fee via Princess to gain entry?