What determines the winner of a virtual PF battle?

Question

I've progressed far enough into the game where I was eligible for virtual battles. Everything seemed pretty straight forward for a while. You "battle" with other PFs and gain points for successful attacks and defenses. Generally, the higher the numbers, the more likely you're able to succeed.

In the beginning, it was almost guaranteed that you would always win attacks and lose on defenses since we tend to build up the combat unit more than the security team. The numbers were generally higher on attack and lower on defense. At higher rankings, I've been winning a lot of defenses, even though I had smaller numbers. There's obviously some randomization going on and the higher the numbers might make it more likely to win. Nowadays, I'm almost never winning anymore since most players have apparently cheated

How did my 450 strong, Level 122 team lose to a Level 0, empty base?

What determines the winner?
How does the Capability number factor in?
How does the Durability number factor in?
How does the Defense Level/Development Grade factor in? Does having a nuke affect the outcome?

All of my forces are generally S+ or S++. I have all of the offline weapons researched and most of the online weapons that can be used by my security teams. My security settings is the advanced settings enough to get the highest level possible. Mother base is fully upgraded while I have two fully upgraded FOBs, one almost fully upgraded FOB, and one more with a couple of platforms. Apparently I've gotten high enough into the rankings that nearly every single player out there has cheated.

Answer 1

Taken from here: http://www.konami.jp/mgs5/tpp/en/base/201512.php5

Each week, your PF Rating will increase if you have placed in the Top 3 in that week’s virtual league battles.

How do I win virtual league battles?

Raising your PF’s [Offensive Capability] and [Durability] will give you an advantage in the attack phase of the automatic battle.

- [Offensive Capability] is based on:

Combat Unit level, combined levels of non-Combat Unit staff, overall equipment grade, resources owned (nuclear weapons, vehicles, fighting vehicles [tanks/armored vehicles], Walker Gears, medicinal plants, parasite canisters)

- [Durability] is based on:

Combat Unit staff numbers, resources owned (processed materials, unprocessed materials), GMP

Raising your PF’s [Defensive Capability] and [Durability] will give you an advantage in the defense phase of the automatic battle.

- [Defensive Capability] is based on:

FOB defense level, Security Team level, Support Unit level, combined levels of non-Security/non-Support staff, number of platforms, resources owned (nuclear weapons, anti-air emplacements, mortars, machine gun emplacements, Walker Gears, medicinal plants, parasite canisters)

- [Durability] is based on:

Security Team staff numbers, number of platforms, resources owned (processed materials, unprocessed materials), number of nuclear weapons owned, GMP

So to address your questions:

The outcomes of the battles are influenced by the Capability and Defence/Offence level, with a bit of a random element thrown in.

So even if your capability and respective level is lower than your opponent's, you can still win, it's just less likely than if your ratings were higher than theirs The quote above it says that these things will "give you an advantage", rather than saying it's a guaranteed win.