Hi,Yes I am referring to the original circuit, but I meant R3 and R4. (Sorry for that mistake) I understand the role of R5 and R6. I actually already made a post about these too, theorising that they are there to narrow the range.
Alright, I see where the issue is now. I didn't consider that rounding would affect the result at a great degree.
R3 and R4 are there to bias the 'diodes'. They need a certain minimum current to work right.