adwords_labels and adwords_groupon Merchant Center Feed Attributes
Can the adwords_grouping attribute only be used on CPA campaigns?
I'm confused about how these attributes are used and what values can be used with them in a product feed. For the adwords_grouping attribute, the Products Feed Specification on Merchant Center States:
"...This is a required field if the advertiser wants to bid differently to different subsets of products in the CPC or CPA % version."
But, the Adwords "Set up your product listing ads campaign" states:
"For CPC bidding: These attributes are condition, brand, product_type, and adwords_labels.
For CPA % bidding: Only adwords_grouping is allowed."
Also, what values can be used with these atributes?
I'm not sure where to post these questions, so I though I would start here.