I am using the following set with a KPI to return the latest CH4 measure value for each Well:

This set returns the current CH4 value for all Wells and current date. I now need to be able to return the second last measure values for all wells for a KPI trend. I cannot use CURRENTMEMBER.PREVMEMBER on the Date dimension as the the measures are not recorded every week, so all the Dates can be different for each measure.

I need to retrieve the second last non empty measure value for each well. Help or guidance appreciated!