Power Pivot and SharePoint Lists

[khwolf]

I am new to Power Pivot and SharePoint. I did some quick searching but could not find an answer to this seemingly simple and likely common problem. I have a Power Pivot model connected to a SharePoint list. The SharePoint list has data with accounts going down and months going across.

Example:
Jan Feb Mar
ExpenseA 1 2 3
ExpenseB 4 5 6

Powerpivot seems to prefer I have the months going down - at least its a lot easier for me to work with it like this.
Example:
ExpenseA Jan 1
ExpenseA Feb 2
ExpenseA Mar 3
ExpenseB Jan 4
ExpenseB Feb 5
ExpenseB Mar 6

But it's very hard for my users to enter data this way. Is there a way to easily convert the data format between SharePoint and PowerPoint?

I have Excel 2013, and Sharepoint 2010

Thanks in advance for any help or hints.