Hi bentupper ,
Thank you very much for your post and the insight.
Yes, their support is absolutely correct.
They are saying that we are using a WC hook to change the product that is passed by parameter and indeed, we are doing that (that's the pure nature of a WP hook). We use this exact hook to record the out of stock date and to check the out of stock threshold.
Also, they are saying that we are redefining the WC_Product type and replacing with our own and that's true, we are doing that to add our extra data to the products, but basically, our product types are clones of the originals but with extra data.
Bad news is that we do not plan to support any 3rd party plugins as ATUM will have its own log premium add-on in 2020 that will pretty much log anything you do with the inventory.
Hope this helps.