We had a custom B2B hotel booking portal developed for our Saint Petersburg-based travel agency. We agreed on an 800,000 RUB fee with a local software agency, and the development process took around 4 months. Last week they deployed the software to our server; basic functions work fine and there are no obvious issues in the UI.
However, during the project wrap-up meeting, the agency manager suggested we get an external "code audit." They told us we could hand this off to an independent expert if we wanted, or their senior architects could prepare a detailed audit report for 120,000 RUB.
This offer makes no sense to me. Why am I being forced to pay extra to audit code that I already paid for and accepted delivery of? What exactly is a code audit, and is it normal for an agency to pitch a service like this for their own work, or is it a sign they don't trust what they wrote?