I'm not sure what you guys are talking about - I know the difference
between an xll and an xla; did you see my post where I said that if I
take an xla rename it to an xll that it works? The issue I'm
experiencing is that I have to hit enter on the formula in order to get
it to work but that shouldn't be due to the xll. If you have a
suggestion as to how to solve my issue let me know.

Rob van Gelder wrote:
The two formats are incompatible.
You cannot pretend that an XLA is an XLL - Excel will notice the difference.

To write an XLL, you need to write it in a language which can compile DLLs -
such as C.

William Hooper has some good info on XLLs at:
http://www.whooper.co.uk/excelstuff.htm


If the XLL functions are used in only one workbook, you could skip the
add-in drama and include the functions in the workbook itself.