(case when EXTRACT(YEAR from {custbody_mn_startship}) = '2019' then {amount} end) - (case when EXTRACT(YEAR from {custbody_mn_startship}) = '2020' then {amount} end)

kindly confirm if my understanding is correct: you want like let's say column 1 and 2 have results derived from formulas and you want the difference of the summed results of each column (not the bottom line summary figures) then try this: Formula (Currency) | Summary Type = Sum| Formula = sum(case when EXTRACT(YEAR from {custbody_mn_startship}) = '2019' then {amount} end) - sum(case when EXTRACT(YEAR from {custbody_mn_startship}) = '2020' then {amount} end)