Is it ok to ask an agent to participate only in certain deals?

[Jose Batista Abikarram]

Here is the situation

I bought my first house with an agent and they were really good and I would like to use them again. However this agent requests you to sign a contract with them basically saying that anything you find should be disclosed to them (In or out of the MLS). Knowing that this was my first relationship I agreed with this term since I understand they only make money when a house is closed. After establishing my relationship and closing successfully I wanted to ask them to consider helping me with all deals found in the MLS and they would get a higher % than normal, but if I found one by myself out of MLS (direct mail marketing, door knocking, etc.) I would do the negotiating and they would not get their %. Even after a relationship and proving that I could be valuable they rejected this request and said that it only works if I do all deals with them.

Am I wrong to think that this is a bit too much, or are all agents expecting to reap the benefits of a client’s research? I want to know the perspectives of the agents and relatora here. Maybe there is something I’m missing!