Re: inspectors vs plan reviewers
Plan review is one of the tasks charged to the building official. He may hire it done, do it himself or delegate it to a subordinate. Small towns will only have one person to do all tasks, larger towns can specialize.
The hierarchy is always: The BO is the boss, he may have assistant BOs, he may have plan reviewers, he may have inspectors who are specialists (electrical, plumbing, construction, residential, commercial, etc.), he may have clerical help.
You can't say the inspector is higher than the plan reviewer because they are both under the BO, it is just that the inspector on the job can discover many more violations than the plan reviewer can by studying the plans.
Many towns will send the plans out to be reviewed, which is sometimes a good thing, as it is easier to blame "them" for missed items than the guy in the next office, who may say "wait a minute...."
The bottom line is that it is impossible for inspectors to catch everything. The contractor is the one responsible for installing everything correctly. When the BO signs the CO he will state "substantially in compliance with the plans".