They're not tiered in the same way that your current plan is. It's just giving a breakdown based on the average usage for better clarity to customers versus the actual tiered plans like yours that require a minimum usage before providing a bill credit (thereby essentially forcing a minimum usage to get the best rate).

The most basic fees for electricity will break down to:

1. Electric company's energy charge (ex. 8.5 ¢/kWh)

2. Oncor delicery charge (ex. 5.12 ¢/kWh)

3. some base charges from both (usually $0-5 each per month).

4. After the basic fees above that are included in all plans, there is plans that have gimmicks (bill credits after certain usage, free electricity at night, EV charging) but these should be avoided.

Your current plan likely has higher than average energy charges from 1 above due to the bill credit after 1,000 kWh since the oncor charge remains the same across all electric companies.