We stopped offering paid support because we got too many requests for it. Not enough time in the world. 🙁 Gotta keep our focus on Pro, rather than making one site look good, we like to make them all look/work well! We usually recommend codeable.io for third party custom dev works. Never heard a complaint about them and they are all WooCommerce / WC Vendors Free/Pro certified.
For filters like that, you’ll always want to hard code teh commission values. Dont rely on functions to look up commission rates, the filters you’re using override them and they may not actually work. The filter is top dog. It overrides *everything*. Keep at it, you’ll get it working soon enough!