The store_code ID sent in the LIA feed is for a random store ID from the Cloud and not the one Google needs (store code from Google Business Profile). If you can enter your Google store ID in a field in the Cloud and the LIA feed can include it instead and at the same time get price/sale_price included, you will be able to implement the LIA feed directly in Merchant Center. Right now, it requires it to go through a feed tool (and potential increased spending on this).