That is actually a good question. Honestly, look at the description of the abilities themselves, specifically Death Lotus. Attack damage here has a better ratio for damage but it states that it deals 'magic damage' either way. It just bases the amount of damage dealt on the greater percentage between attack damage and ability power.

umm why have magic penetration runes if you aren't going AP?? :D
Know it is a old guide but try HeAt's guide both AP and AD works just fine :)

As an AD build u concentrate on getting your AP moves first? Also the runes i see no armor pen, from what i can tell your mastery build are off as well. To much spent in unneeded areas. 2 thumbs down

1. ap does effect turrets, noob. 2. 1v1 kat doesnt prove anything its a team game, 5v5

HeAt, who are you again?
One, AP doesnt affect turrets.
Two, come on, let's 1v1, and i'll prove you wrong.

Madred's Bloodrazor? with only 40% AS?

i dont think that Death Lotus or any other ability implements on hit effects?
correct me if i am wrong.

Ap hurts turrets equally to attack, i suggest you learn your metagame before posting a build my friend. There is no point in giving you a (-) but honestly, dont act like ur running show on my build if you dont know the basics. Gg Man
- HeAt