You need to look up "net listings" as an agent and how you construct your arrangement so that you stay clear of failing to represent a seller, netting an undisclosed profit, ethical issues as well as legal snags.

Most are ethical, and don't mark up $47K 30 days after a purchase.

Wouldn't that be construed as a violation of the long list of ethics rules TREC has?  

Once you are aware, beyond the law, there are liability and ethical concerns. 

The last thing I want is legal trouble.However, is there a time-frame one should ethically wait?

Is it ethical?

I hope to become an example of productivity and work ethic.

RE is a dog eat dog business, in many ways RE isn't regulated dictating ethical conduct and you'll find those "cheating hearts" in RE.

However, if a listing agent advocates for one offer versus the other based on how much commission he gets, he's in ethic violation with his client (i.e.

Lucky for me, I eat very well, sleep well too as all of my money was earned ethically without deceiving anyone.