SC cutter not cutting in circle!

[lukejian 0]

i drew a tiny one and a medium size one with inkscape. When i output them into signcut Pro, the circle is out of round, a bit off but not big deal. However, when i start the cutting with my SC cutter, these circles are way off, not rounded. How do i solve this?

PS: when i drew them in inkscape, i entered the values of H and W at the same number, so i am sure its in a round in inkscape. Signcut makes it a bit off, and SC cutter makes it even worse...

medium size refers to iphone home button size

tiny refers to front camera size.

thank you guys.