Hi Rexy,
“Per Service Load Distribution” is general term/name used that referring to traffic distribution over the available Internet links base on configurable proportions. Distribution of each traffic type can be independently configured according to protocol and port number.
For more information, please refer the URL below:
http://www.peplink.com/knowledgebase/understanding-configuring-outbound-traffic-rules/
Regarding to the WIFI TX power of the Max Transit, i will get back shorty.
Thank You