MATLAB: Open an Excel add-in from MATLAB

actxserveradd-inaddinexcelinvokeMATLABudfxlswrite

Hello
I am able to use actxserver to open an excel workbook and make it visible. I then put data into excel using xlswrite into cell A1. I want excel to perform calculations using an add-in. The value always shows #NAME. I believe this is because the add-in is not loaded so how can I do this from MATLAB?
I tried
xlafile = 'theaddinlocationandname.xla'
and I tried
invoke(Excel.Workbooks,'Open','theaddinlocationandname.xla')
"xlafile= 'theaddinlocationandname.xla'" displays when I do not surpress the output and "Interface.000208DA_0000_0000_C000_000000000046" shows for the invoke one.
When I click on the cell where the value should be, this shows 'addinlocationandname.xla'!functionname("input",A1)
To get the add in to run, I have to go to the "data" tab, "edit links", and hit "open source".