Generate signed apk without typing key

First of all here goes my signinConfigs:

signingConfigs {
        development {
            storeFile file("mykey.jks") //Path to the keystore file
            keyAlias "mykey"
            storePassword "mykeydev"
            keyPassword "mykeydev"
        }
        production {
            storeFile file("mykey.jks") //Path to the keystore file
            keyAlias "mykey"
            storePassword "mykeyprod"
            keyPassword "mykeyprod"
        }
}

And now my flavors:

productFlavors {
    development{
        applicationId "br.com.myapp.dev"
        signingConfig signingConfigs.development
        resValue "string", "app_name", "DEV"
    }

    production {
        applicationId "br.com.myapp"
        signingConfig signingConfigs.production
        resValue "string", "app_name", "PROD"
    }
}

I have under by buildTypes this:

buildTypes {
    release {
        minifyEnabled false
        productFlavors.production.signingConfig signingConfigs.production
        productFlavors.development.signingConfig signingConfigs.development
    }
}

And here goes my question, Why am I asked for keyPassword and storePassword every time i want to generate a new signed apk file, if all keys and stuff are inside my .gradle file?