Many sites that provide both domain registration and website hosting (GoDaddy, Dynadot, etc.) have two interfaces: a DNS panel administering the domain, which includes setting MX records, the other for managing the hosting (this is usually cPanel, for example). cPanel has an interface for administering email and setting MX records.
This means that if you do not purchase hosting, but instead just use GoDaddy as a domain registrar, you can still use the DNS panel to administer nameservers, etc.
Now suppose that I'm trying to migrate e-mail to an external service, e.g. Google Apps for Work. To do this, I have to change the MX records to point to Google's mail servers.
The question is: in which interface (DNS panel / cPanel) should I change the MX records? Does one of them have strict priority over the other?