Cross tab calculation based on value on the column position

[UseCog]

Hi,

I have a cross tab that shows the last 4 weeks data based on the week which is selected by the user. In cross tab one column on the left side is the weeks which is displayed from a set (calculated based on the selected week). I am getting all the measures correctly in the cells but another requirement is to show the 13 weeks prior data on the next column to each measures. Is there any way to get the current value from the node, so i can use a tuple( like tuple([measure], node(e) - 13))

Any helps would be appreciated

Regards,
UC