You can perform looping using the Do While and Do While Conditional nodes. See the Help documentation for your system and search for "loop" and it will display the topics. The nodes are in the Logistics section of the node library.
The Help is also available online for the latest version of the product:
https://d3sa-preview.infogixsaas.com/docs/dist/help/Default.htm
There is an example data flow that is shipped with the installed software that you can import into your system. It is located in the following directory
<\Data3Sixty Analyze Install Dir>/docs/samples/nodes
e.g. for a default Windows Desktop installation:
C:\Program Files\Data3SixtyAnalyze\docs\samples\nodes
Alternatively, if you have sufficient Python programming skills you could leverage Python scripting within, a Transform node or the Python node.
Re. your second question, I'm not sure I understand what you are trying to achieve. Maybe you could consider providing an equivalent set of calculations in an Excel spreadsheet that would produce the same result.