The plugin works well for many as desired. The issue seen by you is something unrelated to the plugin. This is for sure related to your client's installation. i have been on your demo site and the plugin is working well.
Can you confirm if the upgrade and the old version is deleted from Jacq site.
Do you mean, old version can be deleted? If so, YES.
There is no any special or different way of installation. Install this plugin as you do for other plugins. we are seeing big problems concerning this plugin installed the way you suggested.
What I would like to see is a version that will work exactly like it does on your demo site.
The version in the store is the one you should try.
I will delete the plugin from Jacq site and await you to contact her
Sure. Please let me know if you need any kind of assistance on this.