My intent was to indicate how you can adjust your withholding, not why you might want to adjust your withholding. The reason that you would want to adjust your tax withholding would typically be to avoid having too much withheld such that you end up with an unnecessarily large tax refund while also having enough withholding to avoid an underpayment penalty. I suggest reviewing the IRS web page describing underpayment penalties:
https://www.irs.gov/payments/underpayment-of-estimated-tax-by-individuals-penalty
