KY income tax difference with TAXSIM35

[martinholmer]

The following integration test fails. It is not yet known whether the
tax logic problem is in TAXSIM35 or in the current PEUS code, or
whether there are problems in both models. This topic is meant to
facilitate discussion of why this test fails, primarily by reporting
the results of hand calculations required to fill out the relevant tax
form.

- name: Tax unit with taxsimid 98092 in e21.its.csv and e21.ots.csv
  absolute_error_margin: 0.01
  period: 2021
  input:
    people:
      person1:
        age: 73
        employment_income: 9010
        taxable_interest_income: 5505.0
        ssi: 0  # not in TAXSIM35
        state_supplement: 0  # not in TAXSIM35
        wic: 0  # not in TAXSIM35
        ma_covid_19_essential_employee_premium_pay_program: 0  # not in TAXSIM35
      person2:
        age: 73
        employment_income: 6010
        taxable_interest_income: 5505.0
        ssi: 0  # not in TAXSIM35
        state_supplement: 0  # not in TAXSIM35
        wic: 0  # not in TAXSIM35
        ma_covid_19_essential_employee_premium_pay_program: 0  # not in TAXSIM35
    tax_units:
      tax_unit:
        members: [person1, person2]
        premium_tax_credit: 0  # not in TAXSIM35
        local_income_tax: 0  # not in TAXSIM35
        state_sales_tax: 0  # not in TAXSIM35
        ca_use_tax: 0  # not in TAXSIM35
        il_use_tax: 0  # not in TAXSIM35
        nm_2021_income_rebate: 0  # not in TAXSIM35
        nm_additional_2021_income_rebate: 0  # not in TAXSIM35
        nm_supplemental_2021_income_rebate: 0  # not in TAXSIM35
        ny_supplemental_eitc: 0  # not in TAXSIM35
        ok_use_tax: 0  # not in TAXSIM35
        pa_use_tax: 0  # not in TAXSIM35
        vt_renter_credit: 0  # not in TAXSIM35
    spm_units:
      spm_unit:
        members: [person1, person2]
        snap: 0  # not in TAXSIM35
        tanf: 0  # not in TAXSIM35
    households:
      household:
        members: [person1, person2]
        state_fips: 21  # KY
  output:  # expected results from patched TAXSIM35 2024-02-15 version
    ky_income_tax: 0.00

[PavelMakarchuk]

Hello @martinholmer I believe this difference arises from the difference in tax credit amounts from PE to TAXSIM
TaxSim: $1,032.50
PE: $80

The only credit that could cause such a difference, as far as I can see, is the family size tax credit.
According to my calculations, using the Ky AGI amounts which PE and TaxSim agree on I get the following calculation:

Tax form

This results in a 0% credit. as far as I can see:

Table

I wonder if TAXSIM includes a different calculation or if I missed anything