We have received many requests for an Order Bump object. Hopefully, we can add that soon. In the meantime, our other customers are using an Upsell Object to represent an Order Bump.
Also, you could add a Product Sales-Split to your Sales Page object. For example:
Main Offer (product 1) 70% sales-split @ $37
Order Bump (product 2) 30% sales-split @ $47
Note: In that example below, the Sales Page conversion is set to 10%
You have a few options there for now. Thanks!