Incoming webhook parameters

Incoming webhook parameters

I have an incoming webhook into Flow with info I need to create a Sales Order.  It needs to be a custom function because multiple items are possible.  When I create a custom function to gather all this data, I need 13 parameters to map all this data. 
When I execute the code to test it, I get the following error if the number of parameters are over 10 - "Error Logs of Custom Function : "Error occurred while processing this request. Contact support for more details." 

Is there a limit on the # of parameters in a custom function?  If so, how would I go about getting all my JSON data from the webhook into a custom function?

Thaks,
Andy