I come back with some details. After hours of browsing internet and read tones of posts I got the perfect result converting my ePub to AZW3 file. The result is perfect. Magic I might say. However, I run into another issue. How on Earth shall I upload an AZW3 file on Amazon? The client says he managed once but then he got some restrictions and cannot upload the file. I will send a request to their technical support service.
Anyway, until I figure that out, in my humble opinion to convert an ePub file full of tables into a nice Kindle file, AZW3 is the best option. MOBI is a nightmare format. It works perfectly for simple plain text. Not to mention how stupid is when interpreting *.png files. In MOBI format all *.png files will end up with a white background, while in AZW3 they will stay transparent.
For a better understanding (and this time I will not break any forum's rule nor a copyright law) I will post couple of screenshots to see how perfect a book is looking in AZW3 (AZW3-conversion.png) and how bad is in MOBI (MOBI-conversion.png).
My apologizes for administrator of this forum for breaking the rule. I am sorry. I'll be careful next time.