Simple, in fact.
There's a secret member of the ScriptInfo element. It's called "InstallDir" and allows the developer to set a different installation folder.
For example, if you want to call your script "Hello World!" but you want to install it in "HelloWorld", you could use this for your ScriptInfo.xml file:
<?xml version="1.0" encoding="Unicode"?>
<ScriptInfo xmlns="urn:msgplus:scripts" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<Description>This script greets the world!</Description>
This has been used by Screenshot Sender, it installs to "Screenshot Sender 4" but the name is just "Screenshot Sender".
However, if you don't like the name of the installation directory of your old script, this won't have much use...