A spanner has been thrown in the works of one of the Education Minister's cherished policies as primary heads urge members to boycott personal learning planning (PLP) unless more resources are provided.
But the horse may have already bolted from the stable, with many schools embracing personal learning plans and some pronouncing them a success.
The Association of Head Teachers in Scotland accepts that the plans are "a useful tool to measure and record pupil performance". But it says the message from schools is that it is "very resource-intensive", and members should "not embark upon PLP in their schools unless appropriate resources are in place to provide classroom cover for teachers engaged in the scheme".
The approach, which Peter Peacock regards as fundamental to modernising schools and raising attainment, has been piloted in 32 schools. Evidence from the evaluation has shown major benefits in recording and assessment.
But the AHTS insists this glosses over the significant issues of manageability and workload.
The association points out that there is no time-scale within which schools are expected to become involved and it therefore advises members that schools should do so only when they feel they are ready. Mr Peacock has repeatedly stressed his view that PLP should be a natural part of effective practice in schools - what he calls "conversations with pupils".
Falkirk is one authority which believes it has got the recipe right, and has reached the stage where every pupil now has a personal learning plan.
Lynne Grant, a teacher at Deanburn primary in Falkirk who has been seconded to help introduce PLP, says there has been "very positive feedback from staff who appreciate the phased approach we are taking".
PLP is operating in all Falkirk primaries at present and, with primary 7 pupils moving on to secondary with their plans in August, it will start in S1 from the start of the new session.
Falkirk has also taken the decision to phase in the five "life skills" elements of the learning plans, beginning with personal, social and learning skills and either communication skills or numerical skills. The other skills will be added later - problem-solving, researching and thinking, along with co-ordination and movement.
Ms Grant said this is being linked to pupils' progress reports and is about sharing decisions on learning with pupils. If learning outcomes had to be established for every aspect of the traditional subject curriculum, "that would have been a workload issue".