The pound;250,000 job evaluation and pay check commissioned for the inquiry - which spent half its budget on it - is almost certain to be introduced into a test case in front of a Glasgow employment tribunal that has been running for the past year and will continue well into next year.
More than 600 primary heads have submitted claims against authorities across Scotland and are demanding five years' back pay. The Equal Opportunities Commission is funding their battle.
Bill Milligan, president of the Association of Head Teachers in Scotland, said this week: "Clearly, the McCrone recommendation for parity of salary for heads and deputes between primary and secondary can only be good news for us. We are proposing to cite the McCrone committee report."
Authorities, however, will continue to maintain that heads have different functions and responsibilities. More acutely, informed estimates suggest the cost of bringing 2,300 primary heads and deputes into line with secondary colleagues could reach pound;188 milion - virtually the baseline cost of the entire McCrone proposals.
They will argue that the committee's research was not a full job evaluation and therefore produced flawed results. There is no specific argument in the final report for pay parity.
It is understood discussions by Professor Gavin McCrone's committee provoked a division between its two headteacher members, Patricia McCall, of Campie primary, Musselburgh, and Anne Mulgrew, of St Andrew's High, East Kilbride. A confidential 60-page report provided the basis of the inquiry's summary.
Stuart Neilson, AHTS solicitor, said: "Under the Equal Pay Act, if you can point to a job evaluation exercise, you can be entitled to equal pay." Mr Neilson admitted early indications were that the tribunal would not accept the new evidence but said: "If it does not, we will launch a fresh claim. The McCrone committee was very helpful to our point of view."
Mr Milligan, head of Dalmilling primary, Ayr, said: "We are determined we will remain professional throughout and we are not in the business of throwing rocks. If the McCrone recommendations were to be instituted, we would have to consider our position."