When the incremental flow is enabled, only new incremental-friendly suggestions can be applied in later steps. This limits the size of timing improvements but helps maintain stability.
Applying suggestions at opt_design before starting the incremental flow
can allow larger-impact changes. However, some suggestions might need to be disabled if
they cause timing degradation.
If the incremental flow switches to the default flow because of a poor-quality reference checkpoint, all suggestions can be applied.
Note: The QoR Suggestion and Incremental flow is supported
only for UltraScale and UltraScale+ devices.