yeah but the important thing to note here is that the 30% hp is derived from the base hp of lugan.
i think this is where alot of people are confused. Here is why i have noticed this and can clarify.
You say chopper hp is 7919 and the shield is 6665, that is incorrect.
4045 is the amount of shield applied to the Chopper because as you can see if you look carefully the shield only covers about half.
4045 is the 30% of the base hp of lugan, this is also good to know for further tweaking of stats and i don't know why this is not covered anywhere.