It's not "tricky". It is what it is. Current income is the king here. State each income by taking the gross pay, for a full pay period times the number of pay periods in a whole year, so times 12, 26, 24, or 52. The form will combine those incomes automatically once entered. You do not have to qualify with any past year's income. Document the current income with a copy of each latest pay stub. You will get a case note that everybody whose last tax return doesn't show qualifying income. Just ignore the notice, and expect success at interview.