Statistics, incomprehensible points (Grand Theft Auto 4)

I bring to the ideal a complete, 100% + passage of GTA 4 and once again faced with the fact that some statistics raise questions, but how are they formed at all? At first there was an idea to start discussions of this topic in your ideal passage already created by me.
I came to the conclusion that this issue may be wider, and deserves its own topic and is not limited to GTA 4. I would like to collect it more or less together - in one topic.

I’ll start with two points:

1) The degree of addiction to the game (Choose life or Choose life is really the last? but what about in episodes, because they are designed for significantly less gameplay time. There is also no clear answer on foreign resources even about GTA 4 itself, not to mention ELFC.

2) The percentage of those killed during free shooting (it’s generally not clear what and how it is considered, because of this, in Tbogt I never fired from armored personnel carriers and Buzzard machine guns, since after the first (!) Shot they reduce this percentage, but it’s all the same incomplete gameplay for me, when I try to "hook" all the content conceived by the developers. I tried to leave the wounded without finishing off, moving away from the distance of "unloading" these NPCs from the memory, but this does not reduce the percentage)