Yes; the day ahead pricing only applies to the energy generation, which is a competitive market. All energy still flows through the ONCOR lines. Here's an example during peak hours. If I can chop off just this 1 hour every day, it goes a long way.

The only way to reduce the ONCOR charges is either higher uptime (higher load factor), or to not use ONCOR's transformers. I think it can go as low as 0.8¢ by taking power straight from the utility poles (5-20 kV), although I expect 1.8¢ in most small warehouses.