layers in Garmin Maps

I am able to use Garmin maps sourced from http://shonkylogic.net/shonkymaps/ on Oruxmaps. These Garmin maps can be freely downloaded.
The problem I have is the way Oruxmaps displays different layers or details on this garmin map.
If I view this map on Garmin Mapsource, I can get very good detail when zooming in close. In Oruxmap, it does not increase level of detail when zooming in closer than 6km on the scale.
Is there a way of increasing detail for Garmin maps in Oruxmaps?

I have set zoom to be "combined zoom" for all zoom settings
Garmin map settings used:
Use Antaliasing
Show POI
Show Line Labels
Letter size = 7