Jungle Wars: Are three coins random?

Jordanfa asks if the award of three coins after some victories is random.

Over in Kong, Talt24 answers that it's based on the quality of the attack - it's not random. Here is the comment:

The system rewards cheap victories and it punishes expensive victories.

"Punish" may not be the right word because if the attacker plays overkill, he will still win at least one cup but the system will take away clan cups.

But if the attack is with cheap troops, with fewer spells and no golem, three coins may be awarded. As Talt says, it depends on how the system calculates the strength of the defense vs. the strength of the attack.

Astralwyrm, formerly number 1, relies heavily on warriors, even at his level.

What is randomly distributed is gems. Or so it seems.