The thing about starting out with a "good" agent is that the agent realizes that their job isn't just to sell you "A" house, but to help you find the "right" house. So if this deal doesn't work out, well, we'll just go on to the next.
But, Mark didn't start out with an agent, so, here he is, in a less-than-ideal situation.
Can you imagine having the same coach for both players? Do you think they would really give both of you the information needed to win?
Same thing here, your agent is in the other fellows corner and that could really hurt you.
The thing about shopping WITH an agent is that you get to learn a lot about each other; the agent gets to learn what your objectives are and is able to distill strategies to help you get there.
Right now, you're kind of in the position where nobody cares as much about you as they care about the deal, however, that isn't the worst thing in the world.
The agent isn't going to be able to sell your home unless you buy this one, so they do have some incentive to keep the first deal together. If you "go and get your own agent," they may have different incentives; one risk is that they elect to play The Knight On The White Horse, "save" you from this deal, and lead you down a path to who knows where.
I do suggest you hedge your bet here, and consult with an attorney with experience in new construction, to help you understand the builder's addenda, your warranty rights, and advise you on matters that the agent may not be able to.
All the best,
Jason Stevens, GRI,ABR
Kevin Flynn Realty, Inc.