- Have you tried updating Excel to a current, supported version? (ie use ".xlsx" instead of ".xls")
- Have you tried showing a YouTube video of some kittens while they wait?
If you take a look at the requirements of reading an ".xlsx" (or the older ".xls") file, you will realize that it is not as straight forward as reading a CSV file.
In other words : I see nothing wrong. Parsing the old ".xls" file format will always take longer than parsing a CSV file.
The plugin you reference is pure-PL/SQL. As such, it can run on XE editions of the Oracle database.
If you need the process to go faster, then you will need a non-XE database so that you can run a Java version of the plugin.
I don't know if the author, Anton ( ascheffer ), has created a Java version of the Plugin. Try searching his blog/company's site.
Personally, any process that can take over 30 seconds should be processed in the background.
(This can't be done with the plug-in)