L3DT - not enough smoothed terrain

Hi guys - after my several issues I managed to solve them by my self, but now I have only cosmetic problem with my custom maps. As you can see on screen below Heightmap is almost perfectly smoothed.
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But in the end in game map looks like this:
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I'm guessing it has something with image depth.
Output RAW from L3DT is 16 BIT, but Metin2 map convertert by BlackYuko decreases RAW depth to 8Bit causing such rough ground.

I would be much satisfied if somenone could help me to navigate me to right way in map making.

The Height maps in metin2 supports only a certain number of vertexes, so you cant smooth them more than you could see ingame. ;)

kind regards
xF4ke

Let me guess... 255 (8 bit).
Am I correct?

However there are several maps in Metin2, wich they have rounded hills like Seungryong Valley:
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Or DoyyumHwaji
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Or (Best example) Yong-Bi desert
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