QTR-Quadtone RIP

I was trying some new paper today and accidently loaded a PSD image 
into QTR without first converting it to a tiff.  

It printed just fine. 

The image was an 8-bit RGB converted to black and white in CS3 using 
the built in conversion tool. After making the converson, I had 
forgotten to change the file format. 

I was under the impression that QTR only printed TIFFs.  

Did I miss something somewhere?

I am currently using version 2.52.1


ADT