I didn't say your numbers were incorrect - but that they had no relevance to the discussion of the tax burdern people of various income strata are carrying with respect to their income and the impact said tax burden has on them economically.
Your point would be correct if we had a flat tax or a reverse taxation system where people of higher incomes paid a lower %, so it obviously has little to no bearing on a discussion as to which income group should be bearing more of the tax burden OR which group could benefit more from a tax cut.
People in the lower 80% income wise spend tax cuts on bills, their children and/or it might enable them to actually save or build significant savings.
If you're in the top 20%, it's fairly easy to save and meet all your expenses so a tax cut doesn't typically transfer to an improvement in economic quality of life.
Economic Quality of Life is the focal point for the tax burden discussion, not 4th grade math as to a group that earns the majority of the income paying the majority of the taxes.
Your original "point" means absolutely nothing with respect to this discussion.