Nietzsche's Economic Claims (Creditor/Debtor Relationship)

So far, Nietzsche's second essay intrigues me the most. In this essay, there is a strong economic tone is entrenched in this idea of the creditor/debtor relationship. Stemming from Nietzsche's history of promises and memory, the concept of costs and prices (not in a monetary sense, but a morality one). 

Historically, man was primitive in the sense that our animal instincts valued the strong, while glorifying violence as a necessity to life. While the strong only dealt with the strong, making promises was economically beneficial to the two parties. If there were no benefits in making promises,  then it would not have existed. This benefit to man explains why promises are carried out. In order for both parties to benefit, the promises must be kept by memory. This is what I understand that Nietzsche's logic lies but I am still unconvinced of this history. This origin of memory is hard to swallow since memory technically is not born out of a concept. Memory is just an operational function of the brain. With that in mind, it is imperative to remember the promises that are made. Nietzsche does not associate kept promises on the grounds of economic benefits, but on the grounds of pain. I think that this is where he bends his ideas a little too far for me to completely appreciate. Memory is not just grounding to avoid pain, but memory is for both the benefactors of an agreement. The way that my ideas carry is like this: agreements are made to benefit both parties, then memory comes into play because the party wants to benefit. The way that Nietzsche depicts it is that memory comes into play because if one does not remember, then pain is in the near future. 

I think that this is such a negative twist of logic. Even though Nietzsche continues with the creditor/debtor relationship and the concept of "owe" and "guilt", I do not think that this is the important part. To me, what is important is this idea that in the creditor/debtor relationship, there is always a hierarchy. I do not think that this is true. When a promise is made, one party is not better than another party. But the party that fulfills the promise is obviously better than the party that does not fulfill the promise, only leaving me to think that promises should not be made if it cannot be kept. Economically, one would not get into a promise if it is not beneficial. 

In my opinion, people do not weigh the cost of an action out of the need to punish those who do not follow through with the promises, but people weigh the cost and prices of actions and promises at the time that the promises are made. 

Tell me what you think. I feel like I am rambling on.