PCQ Load Balancing Problem

I have CCR1036-12G-4S with RouterOS 6.19 installed. I have 2 WAN links one with 45 Mbps and one with 20 Mbps. I have configured my router for load balancing from http://wiki.mikrotik.com/wiki/Manual:PCC with pcq as both addresses and ports. But I have a problem with this. I am getting traffic only on WAN1 45 Mbps but not on WAN2 20 Mbps. When WAN1 is not working, WAN2 traffic is there and failover is working. When WAN1 is online, WAN2 traffic will stop and goes to WAN1. I want to use both links at the same time for higher bandwidth when both links are ok.

What is the issue with Load Balancing?