Parents and their children were left angry and upset after a blunder led to more than 30 pupils in Northern Ireland receiving the wrong results in their transfer test.
A handful of the youngsters had their hopes dashed when their grades were lowered.
It is believed that 34 pupils from four primary schools received incorrect results from the test provider, GL Assessment. The unregulated test – one of two types in Northern Ireland – is used mostly by Catholic schools.
Among the schools affected were Bellaghy Primary and Rainey Endowed in Magherafelt.
Rainey principal Mark McCullough said the majority who received incorrect scores had had their marks increased.
However, some had their results lowered.
Eleven-year-old Bellaghy Primary pupil Joshua Overend's results went down.
His mother, UUP Assembly Member Sandra Overend, said: "It is terrible, because we try not to put pressure on our children and to take everything in their stride,
"He thought he had done so well. All day we tried to make him feel he still did well."
Mrs Overend added: "As far as I'm concerned the schools acted swiftly as soon as they knew."
But she said an explanation was still needed.
A spokesperson for GL could not be contacted for comment last night.
Mrs Overend was speaking as thousands of children received the results of the entrance test examinations on Saturday.
Also getting his results was 10-year-old Alex McGreevy from Belfast.
He sat four exams – three assessments for the AQE and one for the GL – and got an A grade in one test and scored "well above" the average performance in the second.
His parents Alex and Fi McGreevy said they were delighted with his results, but said the system needed to be clarified.
Mr McGreevy said: "There is anxiety leading up to the test, there is anxiety afterwards and an anxiety period between the conclusion of them and the February 1 results.
"One minute he was very proud at what he had achieved. And within an hour he was heartbroken because one of his best friends didn't perform as well," he added.
A letter telling parents which school has accepted their child will arrive on May 24.
Grammar schools use the AQE (Association of Quality Education) tests in English and maths to select pupils. A second type of exam the GL Assessment is used mostly by Catholic schools. It is the fifth year that unregulated tests have taken the place of the previous 11-plus, which was abolished by the Department of Education.