LOC isnt the only criterion in marking your project.
It also depends on presentation, user interface design, the logic used, the complexity of the logic, the programming logic used, the front-end and back-end used (along with a proper justification of the same), compatibility, future expansion scope etc.
PS: I dunno how its like in Engg, but generally these are some of the criteria used by examiners to judge the project and assign marks.
Oh and you and your team (if any) should be able to answer all the questions that are directed at you by the examiner.