Most of the Pokedex books that I have seen are incorrect and poorly put together. Not sure how they get published, to be honest. What those quotes are attempting to explain is that if a move is the same type of the Poke using it, it will get a 1.5x SameiType Attack Bonus (STAB) increase. That doesn't mean though that it is 2x (or in some cases 4x) effective against an opponent of the same type. For example, even though Swellow gets a STAB bonus, it doesn't gain any additional bonus when attacking another Flying-type like it would a Bug/Fighting/Grass-type.
WARNING: If you have no intention of ever battling against anyone besides the pathetic AI, stop reading now. This won't apply to you. Just use whatever six Pokes you want and enjoy life.
As for your team, the in-game AI is so pathetic that you really can throw six Pokes together and really think that you have a good team. The AI was made that way on purpose. First, so that six-year olds could beat the game, but secondly so you could use the Pokes that you like and still win. Personally, I think that is totally flawed thinking since all that does is teach bad strategy to too many trainers. Keep in mind that with Diamond/Pearl, and the DS, there is now a Wi-Fi feature that is going to allow you the ability to battle other people.
What is going to happen is you have someone who has only played against the pathetic AI and used to playing that way, only to be utterly destroyed when they play someone else. Competitive/link battling is totatlly different than in-game. A real person isn't going to be stupid enough not to switch out when you put their Poke to sleep or bring out a Poke that has an advantage over theirs. A real person also won't rely on mathematical percentages to determine their gameplay. That means no random non-attacking moves, and no horrible movesets (Double Team on Blissey????????).
That is why I am so frustrated with DP and probably won't even spend the money to get one and a DS to play it on. I was really hoping that there would be a difficulty level added, where the AI would actually battle similar to the way a normal person would. With the extra space in the DS, I guess it only afforded them more unnecessary existing Poke evolutions (Roselia is a great example), and marginally better graphics. [/endrant]
When I said your team was poorly put together, that was mainly due to the low levels you had in comparison to L &T's Pokes, which I wrongly thought you were having trouble with. As long as your levels are in the range, your choices are just fine. It is in-game, after all. One of the other biggest differences between in-game and competitive/link battling is strategy. In-game it seems trainers focus mainly on type coverage, which is due to almost every single AI opponent either (a) having an overwhelming weakness by having too many of the same types on their team, or (b) having different types but the levels of them being low enough that you can breeze through them anyway. Again, bad strategy. A good trainer will avoid having more than one of the same weaknesses on their team. So, while type coverage works (too) easily in-game, in competitive/link battling you are better off with stat coverage. You want a team that has some Pokes that can attack, some Pokes that can take hits, and one or two that can assist your team and even inflict statuses on your opponent. That is a big difference in strategy that just doesn't translate from the in-game environment.
After all that, the bottom line is if you are only going to play against the AI, you can disregard anything I have said over the past few paragraphs and enjoy the game as much as you can.
