I would think the dealer is blowing smoke up your *****...
I had never tackled balljoints previously, and did the passenger side complete start to finish in 5 hours. . And I had to run around and find someone to press out/in the joints. .
My truck had 190k on it and they were no joy to remove, but it was about 15 minutes of "what will work here" and they were off...
If the mechanic at the dealer who is "trained and certified" can't remove a hub in less than 5 hours, I'm thinking he's under-educated.
This is how they keep work coming in...
You go tell your buddy, who has similar problems, that "they said" it took 5 hours to just remove the hub, you buddy says "oh *****" I'm not gonna do that, I'll just pay them and it will be easier... And the cycle continues.
Brad