Hi Martin,
If you're describing what I think you're describing, no, nothing you can do. The visual ranges of LODs are hard-coded and the higher the LOD, the shorter the visual range. This is presumably for performance reasons. As LOD gets higher, the number of elevation points increases exponentially, therefore to stabilize the number of elevation points that are drawn, the higher the LOD gets, the shorter the visual range so as to allieviate the number of elevation the terrain engine is forced to draw.
As you fly along, the terrain engine is constantly calculating what to draw, so your aircraft is always at the center of a certain radius of LOD display. The farther terrain is draw at a lower LOD in concentric circles more or less, the farther out, the lower the LOD. The terrain closer to your aircraft is drawn at the prevailing LOD of whatever you have installed. So, for instance, in the Andes, the terrain surrounding your aircraft is drawn at LOD 9 out to, say, 30 km. Beyond that there is a concentric region drawn at LOD 8, and beyond that another drawn at LOD 7, and so on. As you move, these concentric LOD circles follow your movement, so the terrain is constantly morphing to follow your aircraft at the center of these concentric circles.
Unfortunately, this is the way the terrain engine works and there aren't any settings that I am aware of that change that. The alternative would probably be to bog the system down so much that it wold be unflyable. Just one of those performance/detail tradeoffs that we must live with.