You will see the full efforts at level 100. Based off some calculations I've done, your Charizard will have a SAtk of 297.87068965517241379310344827586 when it reaches level 100. This gets rounded down to 297. This means its SAtk IV is 10.
This is one of the most helpful threads I've come across with this subject. I didn't understand EVs much either until I read this. Thanks for posting this, dear!!
Mild nature is better than Hardy Nature since it boosts its SAtk which is why it is that much higher. Its IV though is still not good in SAtk. After some calcs, it appears to be 11.