Your night differential is probably taxed weird. Check your stubs

PSA for salaried and hourly night owls: shift differential is normal taxable income, but a lot of payroll systems lump it in oddly and people don't notice they're being shorted. Pull three recent stubs and confirm the diff is (a) actually there, (b) applied to every night hour, and (c) included when they calculate your overtime rate. That last one is the big one — OT should be based on your base + diff, and payroll 'forgets' constantly.