I created a script in MS mac but it will not open in MSE Android. Is this expected behavior?
Yes, I believe this is to be expected. There is a prior post concerning the differences between MathStudio and MathStudio Express. They have separate file formats. Read this post.
You can open MathStudio Express files on the website and they will be converted to the new file format.
If you save these files to Google Drive you can open them from the iOS app and Mac app.