Performance SLA for Maximized Bandwidth SD-WAN

Hi, guys,

We are using the FortiOS v6.4.2 for the Forti400e HA.

Some questions for the Maximize Bandwidth (SLA) for SD-WAN :

1. As the attached, if the option "update static route" is not checked, what happens for the "Maximize Bandwidth (SLA) for SD-WAN".

 Noted : each WAN link has its own SLA checking and "update static route" is checked; for link connection failed

2. for the following link :

https://docs.fortinet.com/document/fortigate/6.2.0/cookbook/382233/performance-sla-sla-targets

config system virtual-wan-link
 config health-check
 edit "server"
 set server "208.91.114.182"
 set members 1 2
 config sla
 edit 1
 set link-cost-factor latency jitter packet-loss
 set latency-threshold 10
 set jitter-threshold 10
 set packetloss-threshold 1
 next
 end
 next
 end
end

In my question 1, while "update static route" is not checked, " set link-cost-factor latency jitter packet-loss" is disappeared, 

What does it mean ?

3. If I have multi SD-WAN zones, I can not deploy the WAN load-balancing for SD-WAN ( only option is Maximize Bandwidth) ?

 4. Any documents for more descriptions on Maximize Bandwidth for SD-WAN ( such as, the algorithm, how to share traffic on WAN links - if WAN Link01 has 100Mbps and Link02 has 50Mbps, etc) ?

Many many thanks in advance.