Shipping Not Synced With Flexible Shipping Plugin

Hi there! As I continue to get to the bottom of our shipping issues, we found that we are using a plugin from our wordpress called flexible shipping, in which we manually put in our shipping prices based on product weights. In google listings and ads plugin, we have all our delivery times set as well as automatic sync on for these settings. Is the flexible shipping plugin supported by GMC, and if not, what reccommnded plug-ins do you suggest? Thanks!

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