This would be a comment but I am not allowed still....
You have met the money factor, an invention of some marketing department. It is a function of the capitalized cost and term you agree too.
Money Factor = Total monthly charge/((Net capitalization cost + Residual value) x Term)
Thus, when negotiating a lease, the only thing there is to talk about is the purchase price of the car, which affects the capitalized cost. Residuals are set by whatever third party underwrites the whole thing, so don't try to argue about that. And of course you can pick the term.
0.00375 is the money factor for a 9% APR. Multiply by 2400 to get the APR.
0.00375 * 2400 = 9
If you don't want to do the math, there are tools available online.
Further reading here.