Effective feed settings
It is very important to understand that the effective feed settings actually is a combination of settings at four levels which are listed from less specific to more specific: account, feed, collection and product levels. The more specific level, the higher priority the settings are.
Account level include GMC account shipping and tax settings which you can either import from shop settings or manage manually.
Feed level include settings you input via the feed editor page.
Collection level include basic feed settings (google product category, age group, gender, custom labels, promotion id and included destinations) which will be used if no corresponding data can be derived at the lower levels (product levels). Collection level feed settings can be add/edit for each of the include collections as well as customized collections in feed group settings, and is effective for all the feeds within that feed group.
Product level settings can be accessed from the Shopify product detailed page > More action > Multiple Google Shopping feeds. You can also do bulk product level settings by select multiple products in the Shopify product list page > More action > Multiple Google Shopping feeds. **Maintaining product level feed settings could be cumbersome, so it should only be used as the last resort when the rule based feed is not enough.
The effective feed settings will be a combination of settings at the 4 levels, in which setting at the more specific levels will take precedent over settings at the less specific levels.
For example, if a feed that have shipping settings configured, it will override (or at least combined with) the shipping settings at the account level. Similarly, if a special product have the
material set at the product level, that information will be used for that product in all the feeds that it is included, regardless of what value the
material is set to at the feed level.