Looking at GURPS Powers, p.26, I see that Divine powers have a -10% discount because it is expected that the player character will live a life that is moral according to the divinity in question:
A deity grants you your power. Nothing can prevent your god’s power from reaching you . . . but your patron expects certain behavior in return. The precise details depend on your god.
A good god expects you to lead a virtuous life. The required moral code is a -10-point disadvantage (-10%), typically Honesty (12), Sense of Duty (Coreligionists), or a major Vow.
Very well, it seems that a player character could have a god as a Patron. But looking at the basic book, p. B73:
Minimal Intervention: Your Patron is less useful than its power level would suggest. On a successful appearance roll, the GM makes a reaction roll for your Patron to determine whether it actually provides aid; see Requests for Aid (p. 562). On a Neutral or better reaction, you receive the aid your Patron thinks you need – which may or may not be what you want. This is the classic modifier for gods who have many other minions to aid, and frequently accompanies the Pact limitation (see p. 113). -50%
However, a 10-point Pact would be a 10-point limitation on the “Patron” advantage. Conversely, the moral code for the divinity power source is a general disadvantage on the character.
So my first impression is that I could make a 210-character-point divine superhero who follows a 10-point code of morality; that 10-point code of morality would take 10 points off the total, making the hero a 200-point character. Somewhere in that point total, the character would have Patron (highly accessible +50%, minimal intervention -50%, special abilities +100%, Pact limitation -10%) for 57 points of advantage. However, that 10% Pact limitation looks like it might be double-dipping.
Possibly “pact” should not be given because the moral code only gives its deduction once, at the granted-power level. So perhaps the “Patron” advantage should be 60 points, not 57 points. If it costs 60 points, I think it definitely avoids double-dipping.