Although the independent review found "significant cultural changes" since the incident in October 2008, it said there is "little room for slack" in terms of staffing levels for compliance.
Lesley Douglas resigned as Radio 2 controller in the fallout from the on-air prank by Jonathan Ross and Russell Brand in which they left crude messages for actor Andrew Sachs.
It led to a shake-up in the way the BBC checks that programmes comply with editorial rules and standards.
The review said that the lessons from the incident "have been fully learned and much work has been undertaken to implement them".
The report – commissioned by the BBC Trust – also found there was "stringent policing" of compliance in BBC production.
But the author, former Ofcom executive Tim Suter, singled out BBC Radio 4 as one station where further expenditure is needed to keep on top of the workload.