Problems converting PDF to TIF

Hi list, 

I have a strange issue converting a PDF file to TIF. 
If I do it like this: 

convert testfax.pdf '-compress' 'Fax' '+antialias' '-support' '0' '-filter' 'point' '-resize' '1728' '-density' '204x98' '-monochrome' '-define' 'quantum:polarity=min-is-white' testfax3.tif

The resulting file is: 

TIFF 1728x2236 1728x2236+0+0 DirectClass 1-bit 90.0059kb

If I move the testfax.pdf to the end, like this: 

convert '-compress' 'Fax' '+antialias' '-support' '0' '-filter' 'point' '-resize' '1728' '-density' '204x98' '-monochrome' '-define' 'quantum:polarity=min-is-white' testfax.pdf testfax3.tif

the resulting file is: 

TIFF 1728x1074 1728x1074+0+0 DirectClass 1-bit 44.0859kb

So I am very confused. Any idea why? 


Regards, Cristian