IPS, can you make the products meet all google stuff - schemas? for product, brand, offer etc

Many of the fields most likely are not used by you.  For example, do you even allow reviews of products?  Most users don't even have specific brands to be able to be called out.  And most likely you also don't have a global identifier such as a MPN or ISBN number. 

These fields if available could help with showing up in the Shopping part of Google, but them not existing wont hurt your overall rankings from what Google has posted previously.