adding a 5 Year $20,000 improvement increases depreciation by $4,000 (20% of the $20K) and reduces your rental profit by the same amount. you designated the rental as being eligible for the Qualified Business Income Deduction (form 8995), thus the QBI deduction on line 13 is decreased by 20% of the $4k depreciation increase or the other way around is decreased by 20% of the decrease in profit of $4K - the $800. so net your taxable income went down $3200 (1040 - line 15). but this does not explain your statement that taxes went up that's line 24 (lines 16,17,19, 20 and 23)
