Having left uni last year, I went to 8 interviews for 5 jobs. Basically, for the 3 jobs that i got passed the 'first round' of interviewing, there was always a 'second round' (when it was usually just myself and 1-2 others). I cant imagine a company choosing a new employee from just meeting them for 30 minutes in an interview situation. The 2 other jobs i didnt make it to the second round for, but they both had further interviews .
However from the was you have written the quote above, it sounds like you meant to say "There arent too many jobs around that DONT require more than one interview to get the job, you must have impressed enough to get it", so i may just be supporting your point if that's the case
I would say theres multiple differences, the first being you were just out of uni(as maybe were many of the other applicants for the type of job being discussed). Its MUCH harder to predict how a uni leaver whose never worked will take to a real job, than someone who likely already has experience in the real world at the job in question. In your case, multiple interviews for them to compare and contrast and try to make the best decision on who will be the best worker, as opposed to who did the best at uni, two completely different things.
When you're interviewing people who have the experience and have done the same job before, well that question is essentially gone, with a good reference, or good understanding and being able to talk about what he does on a daily basis, you don't need the follow up interviews.
Likewise it would sound like your interviews had a decent number of people applying. Often you'll find 20 15 minute interviews to get a brief idea and narrow it down to 3-4 applicants who come back for a far more focused/indepth/critical interview wastes less time and becomes an easier choice than interviewing everyone for an hour and finding 10 people who for varying reasons would be perfect for the job.
For all we know the OP was the only one who applied, or the only qualified person, who knows. Basically a single interview is pretty standard, with multiple interviews being more common for uni leavers, and jobs with a huge number of applicants.
In regards to negotiating, you could just ask him brutally honestly, what you can do to get the extra grand, IF you really need it. Probation on lower cost, negotiate an review sooner than would be standard, so if they were thinking a review/expected pay rise was normally going to be every year, ask for the first 2 years to have them every 6 months with the implied intention that averaged out across those 2 years you'd end up with about what you'd expect staying in your current job for 2 years. That way you get the same money and they get to know you're worth the cash.
Obviously depends on the job, but maybe ask them for some kind of performance related bonus to make up the difference, so the harder and better you work for them, the more you receive.
