Hi viksh,
AirAsia rarely enforce strict size and weight restrictions from KL (out of over 20 flights, I have never had my bag measured or weighed at checkin, or at the gate).
I have also never had my bag measured, so 2cm is more than likely to go undetected.
Reminds me of wearing 10 sets of clothing at once at VTE airport, which was the only time they weighed my bag and realised it was 15kg instead of 7 ;-)