The below spreadsheet shows how if GST is raised to 15% and the top income tax rate is reduced to 33% someone earning $14,000 a year will pay 29% tax while someone earning $100,000 will only pay 28% tax.
(This is based on having to spend $15,000 a year to live)
Don’t suppose you’d be willing to make the spreadsheet available and not just the screenshot?
I’ll try but so far have been unsuccessful at loading the raw file.