Hi Wszf5560,
I work with Joe_Intel and thought I would jump in here.
I want to start by making sure I understand your question.
Your initial question seemed to be "do writes to the HDD get calculated into the NAND writes on the SSD". The answer to that is definitely "no". The NAND writes is calculated directly by the controller based on total writes. This includes writes caused by Write Amplification (as you pointed out). Data written to other drives in the system can not affect that indicator since the SSD in question did not do any writing.
I think a comment in your first post may be correct. Your comment was "This accidental discovery confused me now, and the result above make me suspect the theory, Putting IE/Chrome or System cache into other medium/drive saving your SSD's wear.". It appears that write requests are being sent to the SSD even though you have directed the cache to your HDD. Perhaps this is some sort of temporary data that is quickly deleted? This is a question for the OS or software vendor.
I hope this helps. If we still don't fully understand your question, then it might be more effective to speak with one of our support agents. You can find contact information at: Contact Support