Embroidering a design on a different garment/fabric than the one it was originally digitized for can cause all kinds of quality issues. In the real world of embroidery, no design sews great on everything. Since each fabric has different characteristics, a design needs to be digitized differently for each. This is because stitches create tension on fabric. What happens is that it pulls in, in the direction the stitches are made and pushes out in the direction the stitches travel. So a circle becomes an oval and we apply “pull compensation” in the digitizing process.
We also usually finish a circle with a satin border. The border stitches sort of make up the difference and because they are travelling around the design in a satin pattern, they hold the border to a better circle. Different fabrics will give/pull/stretch more that others and the process will need to be repeated. This explains why our digitizing may be a little more expensive than our competitors. We have most designs digitized in three versions. One for polos, one for woven shirts such as denim and one for caps. That usually takes care of 95% of your needs.