I'm not talking about the gross income (AGI for each period is on form 2210, schedule AI line 1 (columns a, b, c and d) and increases for each later period as you expect / describe. I'm talking about the annualized income which is on form 2210, schedule AI line 3 (columns a, b, c and d) which is obtained by multiplying line 1 columns by the multiplier value in line 2 columns. Since the multiplier is larger for earlier periods, the annualized income for an earlier period can be significantly larger than a later period. I'm still trying to find the answer to the original question.
