Gross Taxable is the same value on all the reports and Pay Slips. This value is made up of all taxable Allowances less any before tax deductions like Super Salary Sacrifice and any other taxable Deduction Allowances.
Gross (STP) is the Gross Taxable value plus any After Tax (not taxed) Allowance reporting in STP2, Before Tax Allowances that have been Excluded from STP Reporting.
Note: If you do your Wages and then a supplementary pay slip before creating a bank file, the Gross(STP) value will be incorrect and will exclude the Primary Pay Slip value.