Disputes over data quality are delaying the publication of the latest performance indicators that show the social class of students at each university.
More than 20 institutions disputed the figures that were sent to them for checking earlier this year.
Wrangles over the quality of data used to calculate the indicators mean that publication, which was planned for this month, is now due in September.
Half of the complaints centre on figures that project the outcome for students - such as the likelihood of gaining a degree and the time it takes to achieve one.
Judy Akinbolu, a senior analyst for the Higher Education Funding Council for England, said: "In some cases data quality was not as good as it could have been. We are allowing institutions to amend their data and we are checking their claims, which takes time."
The funding council is also tweaking the performance indicators, following complaints that drop-out rates seemed higher than they should be.
Institutions where a relatively large number of students leave with a qualification below degree level want to ensure these students are not classified as drop outs.
Further adjustments will affect the projected outcomes, which will be presented separately for young and mature students. The information will help potential students to assess their chances of completing the course successfully.
The data were divided by age for the social mix and drop-out rate of each institution in the first set of performance indicators, published last December.
Part-time students will remain excluded from many of the indicators. Tim O'Shea, master of Birkbeck College, which caters almost exclusively to part-time students, said: "Part-time students need to be properly understood. The key is to invest in data collection."
The blurring of the distinction between full-time and part-time students will make the existing performance indicators less useful in future, Professor O'Shea warned.
If student debt increases while the employment market is buoyant, more students will switch to part-time study, he predicts.
"I think performance indicators are necessary, but with a longitudinal component to capture mobility and transfer to other institutions, as well as the resumption of study following time in employment," he said.