So, I think it's entirely feasible that Google have chosen to rank you lower in the page, but with a video rich snippet - but it may not be the case at all, you may have just lost rankings due to an algorithm update.
Video results are often given position 3 in the SERPs, but i've seen them appear elsewhere too. If there are a number of video results for a term which suggests a video result would be the best return i.e: "Tutorial", then these results can rank in the top positions.
However, the question i would be interested to hear the answer to is "Have you lost traffic?". Video rich snippets in position three often have a higher click through rate than the top result. If you've got lots of nice rich snippets (albeit with lower ranking), but are maintaining or growing your traffic - then clearly you're in a better position than you were before.
Google may also choose to not rank video results if it feels like videos are not appropriate for the search query. It's not always consistent with this, which is why you may have got some of your products getting the rich snippets, but not others.
What wont happen is that you receive a main listing and a second video snippet result for the same page. Video results are basically page results, but with extra metadata to indicate that there is a video on the page.
If this has caused you to lose traffic, then you could try putting the videos on a different page (with supporting text and content) for each product - and optimise those pages for longer tail keywords around your product, while letting the main product page rank for the head term. I wouldn't really recommend that though, as it will spread your link equity thinner and seems somewhat superfluous.