Yes, it's the topic that's been brought up over and over again but I have one thing to clarify since this is in regards to the wheels I'm building. I've done my math and my math adds up. I'm also following this article I found on calculating offset: How to Calculate Offset after Lip and/or Barrel Change - StanceWorks and my math agrees with what he calculates.

SO, for those interested. My wheels started life as 15x6.5et36 (1" drop lips for reference).

Now, following the above article (and because all I'm changing is my lips) I'm KEEPING my center position because I'm adding 2" lips to my wheels, making them 15x8et17, because every .5" = -6.35mm of offset and technically I'm adding 1.5" of lip to my wheels ((5.5" barrels, .5" face, 2" lip) - (5.5" barrel, .5" face, 1' drop lip) = 1.5")

So whoever told me that my wheels would now be et0 either can't math or just can't math but yeah, in other words, that article is tops for calculating new offsets when adding lips, or, changing barrel size.