I never add contracts. I deal in lots of threes generally. I will entry 3 or 6 or 10 contracts.
If the same commodity has a new setup, I treat it as a new trade not as an add-on.
If that is the case I now have two trades working and I manage each one separately.

Adding contracts based on profits accumulated only decreases the profit accumulated.
The market doesn't go up (or down ) forever so an add-on is generally too late and too risky.

That's just the way I see it and the way I play it.