Since AccPac uses VBA (Visual Basic for Applications) for its "macros", and you may also be writing in Excel using it's flavour of VBA, learning the Visual Basic syntax may indeed be useful in your work environment.
The difference between VB6 and any of the different VBA's are the "visual" aspects, i.e. forms and controls. The syntax is identical, for example declaring variables or doing a for-next loop is exactly the same in VB6 and VBA. But for example the listbox in VB6 works a little differently then the listbox for Access VBA, or Excel VBA, etc.
It may be possible to do what you want with .NET because .NET can use COM objects, and most applications that have VBA are written as a hierarchy of COM objects. For example, I have written a .NET Web Service that uses AccPac's COM API to import orders. But writing in in VB would have been easier.
So in your case I think learning VB or VBA would be useful.
By the way, here's a link to the AccPac forum. There are a couple of people there who can help you with writing AccPac macros. Believe me, its one of the more arcane arts I've come across.