This is a Code for Tax adjustment in Free text Invoice in axapta. You can try this code in job to check the effect of adjustment.
CustInvoiceTable _custInvoiceTable;
CustInvoiceCalcTax custInvoiceCalcTax;
TaxFreeInvoice _taxFreeInvoice;
TaxRegulation _taxRegulation;
;
ttsbegin;
select firstonly _custInvoiceTable where _custInvoiceTable.InvoiceId == "test5";
custInvoiceCalcTax = new CustInvoiceCalcTax_Table(_custInvoiceTable);
_taxFreeInvoice = new TaxFreeInvoice(custInvoiceCalcTax);
_taxFreeInvoice.calc();
_taxRegulation = TaxRegulation::newTaxRegulation(_taxFreeInvoice);
_taxRegulation.allocateAmount(33.47);
_taxRegulation.saveTaxRegulation();