QTR-Quadtone RIP

Is it still valid, that QTR resamples everything to 720ppi, as Roy 
stated once (in 2008)? From there, QTR will dither to whatever dpi one 
has chosen, right?

If so, then 720ppi is the print resolution I should aim for when doing 
the output-sharpening, and also the one I should give QTR if I want to 
control any resampling of my image.

(Sorry to ask or state what might be evident for some of you, but I 
found that this important information was not as easy to find as I 
expected it to be... :-)

Louis