I'm quite happy not to be from your country. There are other variations of what we do elsewhere but in the UK, tax is deducted by my employer and sent to the "tax man". There are fairly simple ways of calculating how its done but basically, I pay 1/12 of my tax each month. Other deductions aside, I get about £10k tax free per year and pay 23% on the rest. If I was higher paid, some would be at the higher rate.
If I was self employed, I would need to do what you have to do but even a tiny business can deal with PAYE (Pay As You Earn). I ran a payroll once and it took less than 2 days work per month to do about 350 peoples pay & deductions. Your system seems very complicated/labourious.