Utility meter negative offset

My electricity provider caculates monthly usage at noon on the last day of each month. So i want to configure Utility meter with a monthly cycle and a -12h offset. In GUI, i can only set offset in days so i using yaml (following offical doc):

utility_meter:
  Qenergy_monthly_offset:
    source: sensor.spm02v3_energy
    cycle: monthly
    offset: '-12:00'

Error log say offset value cant be negative.
Is there any other way i can make this work. Thank you!