SD-WAN SLA probe packets and update static route

[James_G]

Researching SD-WAN for a new implementation and I am not sure I totally understand two aspects,  probe packets and update static route, see document below.

https://docs.fortinet.com/document/fortigate/6.4.2/administration-guide/580649/link-health-monitor

Firstly, anyone explain probe packets, or is this just enabling / disabling the ping the SLA will send.

Secondly, update static route, will the SLA and SD-WAN rule affect other SD WAN rules if the SLA fails. I have some services that must egress on a specific interface, I have SD-WAN rules listed above that are configured to manual and single interface for specific source / destination, I need following SD-WAN rules to not affect the manual policies. 

edit - 

Think I understand the "update static route", not going to use the option

Probe packets are for latency / jitter etc measurement, trying to work out the destination of the packets

[joru]

Hello can confirm the update static route option of SLA Performance affects the general routing table and with it other SD-WAN rules if they need those same routes at least in a Fortigate in 6.0.6.