=OR(IF(ISNA(VLOOKUP(budgets[[#This Row],[IO description]],budget_source,3,FALSE)),0,(VLOOKUP(budgets[[#This Row],[IO description]],budget_source,3,FALSE))),IF(AND(ISNA(VLOOKUP(budgets[[#This Row],[IO description]],budget_source,3,FALSE)),E2>0),E2,VLOOKUP(budgets[[#This Row],[IO description]],budget_source,3,FALSE)))