The first test case is being raised by the Educational Institute of Scotland, the union that is seen by rivals as the principal defender of the contentious promoted post evaluations carried out by independent consultants from PricewaterhouseCoopers.
Most complaints continue to stream from the secondary sector but the honour of challenging the details of the agreement falls to Maureen Jobson, head of Gorebridge primary, whose husband, Roy, is education director in neighbouring Edinburgh.
Mrs Jobson is contesting Midlothian's decision not to increase her salary to the level set by the consultants. A formal grievance has been issued.
The EIS will stoutly defend the job-sizing agreement and is likely to argue that the authority accepted the terms of the national and local exercise and should therefore accept the outcomes without challenging individual cases.
Since thousands of senior promoted staff remain unhappy with the outcome of job-sizing, and with the EIS, the union is keen to press home the point that there should be no wavering on the local authority side.
Midlothian will claim special circumstances that were overlooked. The EIS will counter that there can be no special circumstances since the agreements were "signed off" locally. That would open the floodgates to thousands of challenges across Scotland.
Mrs Jobson's evaluation, based on a September 2002 return, shows she was covering for her depute who was on long-term sick leave. In effect, she was doing two jobs and it is understood she has been doing that for more than a year.
The consultants absorbed the information and produced a final salary that is believed to be around pound;2,000 higher than heads of similar-sized primaries. But that was not picked up by local job-sizing co-ordinators before the final placings were accepted by both the unions and the authority.
It is believed that Midlothian only cottoned on to the discrepancy later on in the process and declined to uprate the head beyond comparators. The authority will counter that Mrs Jobson is being paid an abnormal rate based on temporary circumstances and well above that of other primary heads.
Donald MacKay, education director, said: "We will not comment on any individual grievance or disciplinary procedure that is coming forward."
In similar vein, the EIS declined to comment on individual cases "particularly where there is the possibility of further action through official channels".
Mrs Jobson said she was "surprised" by events. The money itself is not believed to be the source of the grievance.
Meanwhile, the Scottish Secondary Teachers' Association will shortly dispatch a questionnaire to disgruntled members inviting them to reveal details of their job-sizing outcomes and may launch a legal challenge to the whole process based on the returns.
Despite being a partner in the exercise, the union has sought to distance itself from the findings once it became clear that secondaries appeared to be losing out to primaries. The association may take its discontent to an employment tribunal if its lawyers are convinced about the unfair treatment of groups of members.
Elsewhere, secondary and primary heads' associations are keeping their discontent under wraps, although they share many of the concerns about the way the job-sizing exercise has been dominated by the EIS. Many primary heads, who might have been expected to be supportive, remain unhappy at individual placings and what they allege are obvious discrepancies in the system.