When we are not convinced that the market has been tested to a level that would withstand audit, we may require further quotes or further justification.
Os na fyddwn wedi ein darbwyllo bod y farchnad wedi'i phrofi i lefel a fyddai'n gwrthsefyll archwiliad, efallai y byddwn yn gofyn am ragor o ddyfynbrisiau neu gyfiawnhad pellach.