Not sure if this new job is better or not

It is only the third day so I shouldn't jump to conclusions.
One of the things that bothers me is that I get paid one salary up to 45 hours per week and straight time after that and it turns out that they are very anal about it. Evidently it is very important that I work exactly 45 hours per week and exactly 9 hours per day. I have a task oriented job. I needed fifteen extra minutes to finish what I was doing. What is the big deal if I leave 15 minutes early the next day?
Maybe this sort of thing is normal, but at my previous job I was hourly and it was no big deal if I worked 38 hours or 42 hours or if I left or stayed up to an hour or so as long as I was getting everything done and doing a good job.
There are potential other issue but I won't go into those right now.
I wanted a job that would be more of a challenge so I shouldn't complain that this job looks like it will be a challenge.
Maybe, I'll feel better once we move closer. Right now, I am driving an hour each way on top of the 9 hour work day and 1/2 unpaid lunch.