Around 450 Leaving Certificate students will be getting a higher preference offer, after errors were discovered with the calculated grades system.
The CAO says it is optimistic that all students will be accommodated by third-level institutions.
It hopes to make offers to the students in question on Thursday morning.
Chair of the board of the CAO, Professor Pól Ó Dochartaigh, says the figure is more manageable than initially feared.
"It was never the expectation that there were going to be 6,000 additional offers.
"A lot of people got more points than were needed for their first preference, so an extra 10 points wasn't going to make any difference.
"For others, they may not have got their first preference but the 10 points extra wouldn't necessarily bring them over the threshold to their next highest preference.
"But at one stage we were afraid that it could have been three times that number, I have to say".
A mistake on one line of code has led to around 6,100 students getting a poorer grade than they should.
A total of three errors with the code used in the system have been identified - although a newly-confirmed third issue is not said to have had any meaningful impact on results.
The highest number of upgrades any one student will receive is five.
A total of 6,870 grades were affected by the errors, and 614 of the 741 schools and other centres recognised to hold the Leaving Certificate will have one or more upgraded results.
All students will receive a text message this evening alerting them whether their grades are changing.
Reporting by: Kacey O'Riordan