Compare a measure in different columns/rows for 2 dates (months)

Hi,

I'm using BOXi4.0. Hoping you can help as this one has me puzzled, we have a measure (mMeasureA) and we have a date (dDate) dimension.

I have created a variable to return the 1st of the month from dDate which is working fine and mMeasureA is aggregating in the block (horizontal table) correctly.

What I now want to do is be able to compare 2 columns from within my block, essentially if my data looks like this:

Month          01/Apr          01/May          01/Jun

Measure       15                10                 8

I want to compare each column with the previous one, so i have 2 additional rows which based on the above i'd expect:

Month          01/Apr          01/May          01/Jun

Measure       15                10                 8

NewMes       0                  5                   -2

%                0%                50%              -20%

Can this be done?

Thanks in advance for any help provided.