I know, I have this same issue with my HandFireArms. I had my 870 showing up close then at a distance it looked like a No4 rifle.
I'll use the M10 tank as an example. If you open up its Objects.con and scroll to the bottom, you will see this:
- rem *** M10Simple ***
ObjectTemplate.create SimpleObject M10Simple
ObjectTemplate.geometry M10_Hull_L1
That's what you see from long distances, when the main Complex mesh is out of range. This is, in your case, that BF-109 mesh when you see your vehicle from far away.
This SimpleObject is added to the LOD object, seen here:
- rem *** lodM10 ***
ObjectTemplate.create LodObject lodM10
ObjectTemplate.hasMobilePhysics 1
ObjectTemplate.hasCollisionPhysics 1
ObjectTemplate.hasResponsePhysics 1
rem -------------------------------------
ObjectTemplate.addTemplate M10Complex
ObjectTemplate.addTemplate M10Simple
ObjectTemplate.addTemplate M10Wreck
rem -------------------------------------
ObjectTemplate.lodSelector M10LodSelector
Also note that "M10_Hull_L1" is a different StandardMesh file than the main meshes. It has all of the tank's parts in one single StandardMesh 3D object (turret, hull, tracks), with a reduced poly count. You don't need high poly counts for a far distant object. I've seen them with varying names, such as "ObjectName_L1", "shad_ObjectName", "shade_ObjectName", "shad_ObjectName_m1", etc.