Hi Gabrie, I was trying to get an answer as to why the default for most of the policy templates is 1% - but really you should set that to whatever makes sense for your environment.
For example, you may not care as much about production system being oversized so jack that up to 90% (or even 100% if you want to just ignore oversized all together). For non-prod you may be more conservative, so maybe 30% or lower there, using your ranges.
I always recommend checking the oversized recommendations against a 30 day metric graph for CPU and/or memory utilization to validate peak and duration before changing a VMs allocation.