On any of the trips you are going to have a certain amount of travel time to the fishing location. You aren't going to fish for 8 hours.

The 8 hour trips are most likely going to the North or South Baker Rocks. They're roughly 38 miles out. At 15-20 knots (depending on sea conditions) it takes about 2 hours out and the same back in. You'll generally get 3-4 hours of fishing in. That's why everybody told you to avoid the 5 hour trip. You can't go far enough or get deep enough to catch ant decent fish. You might not even find blue water on the short trips.

And yes, your fee pays for fuel. Those boats don't run on seawater.

Also, the farther offshore you go, the deeper the water is generally. The deeper the water, the more fish there usually are. Typically you need to be in at least 150 feet of water to have a chance at keeper sized fish. 200 feet is better and 300 feet is better yet.

Also, it's best if you're in blue water. The farther offshore you go the better your chances of getting into blue water. The blue water moves with wind and currents, so there's no telling where it will be. Sometimes it's 10 miles offshore and sometimes you can go 60 miles and never find it.

So, the longer the trip, the better your chances of catching a decent stringer of fish and a wider variety of fish.