TLC59116-Q1: I set the REXT,but output current doesn't change as datasheet described

Dear TI Experts,

Now I am using TLC116-Q1 to drive 3 RGB， but I found green led is not as bright as red and blue led~

The current is about 20mA, I change REXT resistance from 720Ω to 360Ω， but led brightness is darkened

According to the  datasheet, the current should be higher, Can I know why？

PS:Now the PWM is set to max brightness,and output voltage is about 2.5V