"Granted"
(Granted that the officers were used to making decisions, they still couldn't be expected to understand.)
と "Even though"
(Even though that the officers were used to making decisions, they still couldn't be expected to understand) はどう違いますか？説明が難しい場合は、例文を教えて下さい。

The two terms are sort of going in the opposite direction.
"Granted" means "I accept this to be true" or "I admit that it is true". I am saying that my opinion is in agreement with your opinion (or someone else's opinion).
"Granted that you are studying very hard, but you still aren't keeping up in class." (I said to my teacher that I am studying very hard, and she agrees [she grants], but that is not enough for the class)
"Granted that learning Portuguese is difficult, but if you continue to study, you will master it quickly." (I said to victorgabriel22_ that Portuguese is a difficult language, and he agreed with my opinion that it was difficult, and he encouraged me to keep studying).
Other people may say that you are not studying enough or that Portuguese is very easy to learn, but I am agreeing (granting) with other opinions or admit that they are true.
"Even though" means that there is a fact that everyone accepts as true (it isn't my opinion), but that fact isn't enough to cause something to happen.
"Even though this car is within our budget, I don't think we should buy it" (Everyone agrees that we can afford this car. That is not in dispute. But being affordable isn't enough reason to buy it).
"Even though it is raining, I am still going to the beach." (Everyone agrees that it is raining. That is a fact. But I am going to the beach despite the rain)
In daily use, "even though" is more common than "granted", and both can have very similar meaning. The difference is that when I grant, I am agreeing that something is true. "Even though" means that something is true. It doesn't need me to agree to it to be true.