Hi @NatS , I’m fairly sure that OVO don’t offer commercial contracts. That might be a restriction. 
As to the balance between domestic and commercial, it probably depends on your consumption 

From what I understand, you probably will be better off on a Domestic supplier and tariff. It’d get rid of all the extra hidden fees and apply certain types of protections that you don’t get on a Non-Domestic tariff like the price caps.

To do this, please switch to a supplier that serves both Domestic and Non-Domestic customers as you are now, then make the request to their customer service to be migrated to Domestic supply. They’ll do the rest (hopefully). After that’s all done, you should have access to all Domestic tariffs including the ones OVO offers.

Hope that helps!