thank you for your screenshots. I hope you will have time to look at mine. To be shorter, I would like to demonstrate you MS Word behavior only, leaving Aspose.Words behind the scene at the moment.
I'm attaching MS Word file with a table with two rows. Visually, they both are black. They look equal in MS Word. But the first is simple black (set by Fill/Black button) and the second one is almost black (set by Fill/More Colors/Custom/R=0,G=0,B=1).
The second attached file is "perfect" PDF saved by MS Word 2007. If you will open it in Adobe Acrobat 9, you notice no difference in black color for these two rows - "perfectly".
Then, please, open "Output preview" (the same as you've done for your screenshots) and wonder. You will see that two rows have significantly different look. Please, move a mouse pointer over one and the other rows (the same as you've done) and wonder again:
First row has C=0,M=0,Y=0,K=100 color
Second row has C=75,M=68,Y=67,K=90 color
Rows of this table will be printed on your printer by two essentially different ways (I suppose, you understand it). I hope this example will help you to understand my points in the previous post: MS Word doesn't save CMYK colors to Pdf. MS Word just does the simplest workaround for R=G=B case (the same as mentioned check mark in Adobe Acrobat) - it saves it in Grayscale color space which perfectly converted to blac(K) ink by Adobe Acrobat.
On your screenshots Adobe Acrobat does not show colors in PDF - it shows CMYK result which is calculated by Adobe Acrobat itself. If you want to see original colors, saved in PDF, you can try to import the PDF into Adobe Illustrator, for example. Or some preflight tool.
Please, try to reread my previous post not as opinion of some guy who doesn't understand what you mean but as professional explanation of a man with more than 5 years experience in colored design and preflight.
Be sure, preflight is not a "check", it's a "work". If "they" just check, someone has to do this work if you want to get good result for full-color documents.