Your welcome.
There is also another thing about elemental weakness.
Using the same example,
-You do 100 fire magic damage
-You have 50 fire property attack
-the monster has 0 magic defense
-the monster is weak to fire
This time I am going to talk about fire property attack first.
-The monster is weak to fire, therefore you do 50% more damage to it
-Since the monster is weak to fire, your fire property attack will increase by 50%
-it will go from 50 -> 75
-Since your magic attack is fire, your magic damage will be increased by 50% as well.
-This 50% increase comes AFTER elemental property attack is applied
-So your magic damage will be 100 + (75 fire property attack)
-Which will then be multiplied by 150%
-It becomes 150 + (112 fire property attack) damage
Essentially, elemental property attack double dips on monsters weak to that element if you are using the same elemental magic attack.