AI unlimited ERS

When i am fighting with AI on a straight, they have much higher straight speed even when i am using ERS and have DRS and they do not have DRS. When i was watching race replay i could see that they pushed the ERS button but the ERS bar on the wheel did not move at all. They were using the ERS all race long and it didn't move at all. And i have equal performance or I should had have equal performance