You can make line spacing in 2 column text at the same level, by following these steps:
1. select the text.
2. open the paragraph dialog box.
3. In the spacing section, make spacing after paragraph 12 pt, and line spacing "Exactly" 12 pt.
4. If you are using Heading Style, make spacing after heading 12 pt.

This work for all types of documents. However, if you use spacing higher than 12 pt you may need to do manual adjustment.