Here's my issue with "90-minute session", a client may go "Well, I only want a 30 minute session, can we do that and I'll give you $50?". Which wouldn't make it worth your while. I don't put a time limit on my portrait sessions. I go until I get what I feel the client is paying for. If I feel we need a few more frames, I will do that. If I feel we nailed it after an hour, I'll be on my way. Here is how I work my prices:
Portraits: $150, includes 2 setting changes within the same location and two outfit changes.
I don't negotiate on that in my actual pricing. If someone e-mails me and says "can we have three outfit changes?" I would respond with "yes, that will be $XX extra". So just do a base price and brief description of what it includes.
As for the actual pricing, I think it's great. It's what I charge. And I actually make a great living. I have a car, live in a nice condo, pay my bills, sure I don't have a lot of "spending" money, but I do photography because I love the art of photography, not to make a million on AND the majority of my clients are military- if I charged any more I'd never work and would go CRAZY with boredom. If you WANT to make a million doing photography, yes, you are not charging nearly enough. But if that's not your goal, your prices are fine.