The increasingly popular practice of pupils "banking" grades for GCSE and A-levels modules towards their final results could be abolished by the exams regulator.
Ofqual is considering the controversial measure as part of a drive to ensure standards are maintained as exams become increasingly modular and unitised.
Under its proposal, individual module marks would stand, but the grades awarded would remain provisional until the overall mark for the qualification had been finalised.
The idea would introduce some scope for change if anything went wrong in a grading process which has become virtually automatic and pre-determined by the grades given to individual modules.
Isabel Nisbet, Ofqual's acting chief executive, described the process as "the ping factor" and said it was important to look at how it affected the regulator's ability to ensure standards remained constant.
"Qualifications that we are being asked to regulate are increasingly modular or unitised," she told a Cambridge Assessment conference this month.
"They are comprised of a number of separate elements, with the outcome for the qualification as a whole determined by the outcomes of the separate elements.
"When the required elements are completed, the outcome is automatic. The machine goes ping and out pops the candidate's results. There is no discretion at the ping stage: it just pops out."
But there was an expectation - and a legal requirement - for Ofqual to ensure standards were maintained in qualifications as a whole rather than only the units and modules that made them up.
Ms Nisbet accepted that there were "clear downsides" to her proposal. Schools and candidates might feel cheated if provisional module grades were changed.
It could encourage "sophisticated game-playing" from schools and colleges in calculating when was a good time to cash in units, she said. It was also likely to be resisted by schools who wanted to be able to predict final grades.
Ms Nisbet ruled out making module grades provisional for "most" modular qualifications, but said it was a "possible goer" for unitised A-levels and GCSEs.
Ofqual has considered allowing the modification or "hyper correction" of a final module as an adjustment mechanism to the overall result, but rejected it as unfair to candidates.
It has ruled out keeping the results of individual modules secret until the whole qualification is complete. It also ditched the idea of changing grade boundaries at overall qualification level and making them different to the modular boundaries.
Asked why there should be doubt about an overall grade when the modules are correct, Ms Nisbet said: "In a perfect qualification, it shouldn't go wrong. But there is a lot difference between design and what actually happens in the real world."
She pointed to last year's controversy over GCSE science - one board had to lower the mark needed to achieve a C grade to bring it into line with the other two boards - as an example of the gap between design and implementation.