Well yes... it does depend on the length of the cruise, but I have not seen many cruises for $300 to $400 pp after you add everything up unless you are looking at a three day cruise.
So I suspect the OP has a pretty good deal... certainly a fair deal, but it all depends on the length of the cruise.
No matter what the cruise line, I want to see the entire price, including the fare, taxes, port fees, and now, I even include the $10 per day tip. Then I divide the total cost by the number of days to figure out my cost per day. To me that is the bottom line.
I have a cruise coming up for 8 days and the total is $699.50. It starts at $559.00 + $60.50 taxes and port fees + $80.00 in tips. That is $87.44 per day. (Or $77.44 per day if I back out the tips)
This included a minimum upgrade to Class 4B, a bottle of wine, and a $50.00 pp onboard credit... because we are part of a group. (if I take the $50.00 OBC out, that reduces my daily cost to $72.44 pp/per day.)
However, this was originally advertised as an IS class at $509 pp. or $63.63 per day. Then the fun begins, and in my opinion, we must add all the taxes, port fees, etc., into the cost. In my case, there are variables because of the size of the group.
Hope this helps... it can be confusing. I just think that we find a deal that we are happy with and can't worry about what the guy in the next cabin paid, because there are always different options.