Tablei not working as I assume it would

Hey Guys, I am looking for someone to explain what I do not understand about the tablei or table opcodes.
I have been working with the waveshaping instrument and phase-quadrature instruments from pages 79 and 85 of The Csound Book, respectively, but I don’t find the table opcode working as I expect it to. I thought that one had to feed the table opcode an index signal in the range of 0 -1 and set mode to 1 and set offset to 0.5 to get the proper output but while working I noticed that if I feed tablei a index in the 0-1 range and with an offset of 0.5 I would only get the top half of a bipolar signal out. Alternatively if I feed it a index ranging from -1 to 1 with an offset of 0, I will only get the bottom half of a bipolar signal out. So the only way to get it to work correctly from what I see is to feed tablei an index ranging from -1 to 1 but with an offset of 0.5 which does not seem intuitive to me. Can anyone explain this behavior to me. I have included screenshots of my phase-quadrature instrument and ftgens.

I just realized I should have been using Gen 15 for this. I still works the same however.