Ronnie Knox, the former principal of North Glasgow College, and John Gray, his vice-principal, received £471,000 between them under the deal, which followed the college's merger with two other institutions to form Glasgow Kelvin College.
Audit Scotland raised the issue of transparency over the way the payments were sanctioned, stating there was no evidence they were subjected to "appropriate approval" or assessed as providing value for money.
But there was no suggestion that the payments were wrongly calculated, illegal or fraudulent.
The size of the payments, approved by the board of the former college and its remuneration committee, sparked concern among politicians on the Scottish Parliament's public audit committee. As a result, Glasgow Kelvin College has asked its auditors to review the payments. A letter to the committee from Kelvin College states the body's external auditors Scott Moncrieff will "further review" the payments.
Auditors will look at the operation of the remuneration committee at the former North Glasgow College and provide further information on why all the costs of the severance packages were not initially identified.
"It is anticipated that this task will require Scott Moncrieff to conduct interviews with the former chair, principal and clerk to the board of North Glasgow College and members of the remuneration committee of that board," it adds.
Caroline Gardner, auditor general for Scotland, has stressed there is no evidence the payments were wrongly calculated, or they were illegal or fraudulent.
However, a report on the issue for Audit Scotland raised the matter of both members of staff being allowed to go on "gardening leave".
It said: "According to the minutes of the remuneration committee, the committee agreed the vice-principal should be offered six months' garden leave on full pay. No details are provided in the minutes of the basis for this decision, including whether it represented value for money.
"I understand the principal was not required to work his notice period beyond October 31. In this case there does not appear to be any minuted decision."
Mr Knox said the way the payments were sanctioned and the amount agreed had been dealt with by the college's remuneration committee under due legal process and he was not privy to any of their discussions.
The use of severance payments in the merger process was seen as an essential short-term measure as overall numbers of executive staff were cut, with savings expected in the long-term.