Somewhere it is posted maybe on ozone or elsewhere that ozone adds its own dithering so make sure other dithers are disabled. I was just reading this somewhere.

Yes, that's correct, dither adds noise and you might not notice it at first but it will be more obvious at the fadeout of a song.
 
On this point about hearing noise on the fadeout, I am only speaking in terms of if you dither twice. With proper single dithering there should be no hint of audible noise added by dithering.
 
Just to clarify.

I agree, I was just replying to BlixYZ who said "If there's nothing left to dither, won't the second dither leave the data untouched?" 
This seems based on a misunderstanding of what dithering actually does, which essentially is "adding noise". 

Sanderxpander
I agree, I was just replying to BlixYZ who said "If there's nothing left to dither, won't the second dither leave the data untouched?" 
This seems based on a misunderstanding of what dithering actually does, which essentially is "adding noise". 

yeah, I was actually agreeing with you and expounding.

I should have put a +1 next to your quote.
 

crude example
 
111111111111111011111111 = 16776959
111111111111111001111111 = 16776831
two different 24 bit voltage levels but when truncated to 16 bit
 
1111111111111110 = 65534
1111111111111110 = 65534
both 16 bit voltage levels are equal
 
if we take a couple of the least significant bits in the 24 bit sample and randomize them (by adding noise to them) before we truncate. we end up with after truncating
 
1111111111111111 = 65535
1111111111111110 = 65534
two different 16 bit voltage levels.
 
over time the added noise will smooth out the truncation error/distortion and sound more pleasing to the ear.