Well, we provide Workbook.CalculateFormula(bool ignoreError, ICustomFunction customFunction) method in Aspose.Cells component for handling custom/user defined functions. So, you can implement the interface and write your own custom function to calculate it for your need.
Also do you have a tech. support #? I tried 888.277.6734 but cannot connect with anyone.
Yes, we do have technical support desk. Generally, we handle client inquires via forums (posts) and Live Chat. When you post a query in the forums, you can expect a reply in quick time. Our support desk is always active in different parts of the word for handling customer inquires. The support desk is collaborative with developers of the products. Moreover, if a client finds a bug or demands a new feature for his need, we do provide him the fixed/supported version of the product at the spot via forums.
Feel free to contact us any time if you need further clarification.