Checking out the new quantity adjustment option:
It only works from the UI. DMT returns NewOnHandQty as an input field but still regards AdjustQuantity as a required field.
REST Swagger doesn’t reveal any InventoryQtyAdjSvc methods, but observing an update from the browser UI does. It’s a series of testing things against three HTTP requests, then setting an adjustment. I haven’t done any testing so can’t say what a REST update would look like or if it requires an AdjustQuantity value.