import Scriv docs with columns from Mac to Windows

When I import a project from Mac (3) to Windows Beta (current version), the original distribution of the vertical columns is not kept in Windows: columns in Windows are automatically set to equal width distribution (for instance, 50%-50% in case of 2 columns; 25%'s in case of 4 columns), while in Mac they had a different distribution in Mac (for example: 30%-50% in the case of 2 columns).
The original Mac file becomes thus distorted in Windows and in the case of 2 columns and 1 row I have to rearrange the parallel paragraphs, a tedious and wasting time process.
Is there a way to avoid this distortion? Is it a bug?