Hi Menion, you know my "addiction" to Lucus since years, but we have to admit there are other people who use other apps in addition or instead.
When testing ANY raster map with Locus and with Orux you notice factors between the scales. For the same map you need a 4x magnifying glass in Orux. And I do not propose a discussion who is right or wrong here.
Alos, for raster maps, the battery argument does not hold, I suppose. Displaying images is highly optimized by Smartphone architecture, more or less tiles do not really matter, hence the scaling below 100% does not hurt. Yet, rendering vector maps is the real battery power burden.
So, to make all ends meet, I propose you give the overview map its own scaling factor, hence vector processing in higher ZLs will not be affected by a scale down.