I'd prefer to use @EXPORT_OK, so I can see where the %instarray has come from. It's usually preferable to be explicit.

Alternatively, to add another degree of maintainability, but at the cost of more typing, you could export nothing and access everything through the full package name. That way when you're getting values out of your hash (or whatever), you know exactly where they've been set. This sort of thing is a huge benefit when you're reading someone else's code - otherwise you end up scanning the whole file trying to figure out where they set a variable.