Texture is not in line in UE4

Hello there, I’m new of UE4 I’m starting right now to playing with.
I was testing the UVs with a temporary diffuse and normal map on the engine and I found a difference on the seam under the nose:
here’s the render with mental ray:

Nose is

this is in UE:

Is subtle but you can see that a seam breaks the normals on the mouth and under the nose the line is not contiguous.

These are the UVs:

Do you think is bad uv mapping? Any advice is very appreciated.

Ps: I’m working in multitile, but that is not really important because is only for practical reasons. But since I’m here I would like to ask:
Is it legit to use 2 materials that differs only for the maps? I mean, I’ll prolly use a mat for the third uv tile, but the first and second ones are PRETTY SIMILAR (fur and bits of skin), I would use one material for these, but AFAIK multitile texture on UE is not so good, is that correct?

I did more investigation and this is what I found, in Maya/Mental ray looks like this:

Instead in UE4:

I really don’t know what to do, I tried to offset the texture but it only gets dumber…

Its because of normal map seam.
Here is a few similar threads for you to read

first of all try to use right green channel in normal map

Well that’s useful, I didn’t really know about that! I’ll sure read some of those threads, thanks!
After a day spent searching for the problem, tweaking uvs, see if exporting worked fine, serach for faulty triangulation problems, at the end, I found out the problem about aligning textures this morning, in the static mesh editor, I had to tick an option about “full precision UVs” to display the maps correctly, this is the result:

I’ve another question, material related for multitiled UVs, I don’t know anything about this:
It is good to use 2 materials on one mesh that differ only on the textures, will it render good? Or is there a way to use more textures with one material?
I mean it’s not a problem to me to use “different” materials on one-piece mesh… I would like to know if it’s good to do this instead of multitile textures.