I hav also the SANTRO CLUB GV.
At first i also feel worried about the mystery of blinking lights.
The BLINKING LIGHTS represent that the CNG tank is full. U can judge the pressure of different GAS STATIONS easily and check wheather it is up to mark or not.
Like when u filled the TANK full, if the lights r blinking then it represents good presure and if lights r not blinking then it represents the bad pressure.
But there seems to be some setting problem as u mentioned it also blinks when tank is half filled.