If your company's product is similar to your handle, I am quite familiar with them. I worked for them and now for a supplier.
As I understand it, they feel that any lofted surface data should be as true to the original lofted data as possible. IGES tends to create unreliable surface data (untrimmed, missing surfaces, etc), and they probably feel that STEP data, while an improvement, may still be lacking true fidelity. I don't think it's so much that UG doesn't support those formats as the company does not want to put it's data into those formats due to reliability.
In our situation, we receive the native part files and work from those. We do have to send files out to mold makers and tooling shops, and while we prefer to keep them native, sometimes there is no choice (that's an aggressive schedule!). Parasolids are our first choice for export, followed by STEP. Fortunately, we inspect the resulting tooling models against the native part files, and this helps us ensure that the data is good.
When we are finished modifiying the customers part models to reflect what we will actually be delivering, we send parasolids back to the customer. They then have a "turnkey" part that should meet their expectations.
Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]