Finding and selling used books on Amazon.com

I am selling used books on amazon.com and have the following question, if any other Amazon sellers here can help (I just spoke to an Amazon phone CSR who could not comprehend the situation).

For a book I want to sell, I will search for it by title on amazon.com to find the appropriate listing under which I want to list mine. My assumption is that a potential buyer is usually searching for a particular book in the same way, by title, and I want to be sure they will find mine. Often there are multiple listings for the same book (for example, different printings in different years). I may or may not find an exact match (year, cover art, etc.) for the book I am selling. Then in another amazon.com browser tab, side by side, I look up the same book by its ISBN and many times I will get an exactly matching listing for the book I want to sell but that listing did not appear when searching by title. My further assumption/concern being that if I use this listing, potential buyers will not find it if/when they search for the book by title, since I did not. Any idea what’s going on here? Thanks.