Colour Experts... my "Piebald?"

[Amy567]

I have a mini shetland mare who has had a white dot on her side ever since we've had her, she's got a bit more white on her now. However, due to this white dot, she's classed as a Piebald in her passport. I wondered if anyone could tell me what her markings actually are?

Here's some photos







The last photo shows the white line that's slowly forming. They are not saddle/rug rubs or fungal infection related.

Thanks in advance

 

[Meowy Catkin]

Looks like sabino to me. The sock on the near hind certainly has the jagged edge that is typical of sabino and it looks like there are white flecks in the coat too.

 

[Amy567]

Thank you I was thinking that it was something along those lines