Averge Step load assertion not working.

1. I have load test that runs >1000 times and usually has average time 1,8 - 3ms  

2. I have Average Step assertion with following settings:

   min req :  100

   max ave : 5

   max err  : 0 (require no error)

   sample :  20

3. I want to check how it works :  i have changed "max ave" to 1 (so I thought it means 1ms - for max average)

4. Test not fails after run while average value was 2,5ms