Hi @felipebenra,
I am not sure if it was because the curve number method does not include the topography, it maybe so. In my case, I did a trial and error to get into the benchmark value as close as possible. alpha was default but beta and gamma was through trial and error combination. It seems their combination makes a significant difference. I ended up using alpha = 1/12, beta = 1.5, gamma = 2.3492 or 2.3493.
Stacy is right, you need to convert the results first to unit/time/area. In my case, I used a m/s/pixel (where 1 pixel = 1sqm). The process for that computation was also mentioned by Victor in this thread.
Hope this helps.