it does seem to be over charged.
a couple things to consider:
driving time; it is often charged. when you ask about the time charged, you can find that out then and why you would have been charged possibly 4 1/2 hours drive time.
when the guy left, what was he doing? If he was running for parts, fine. If he was eating lunch, checking on another job, or visiting his girlfriend, he should not be charging you for the time.
who brought the parts? If the second guy did, there could be time getting parts before he got to your house that is chargeable.
I did notice one thing. In your list of time, you included this:
so they hooked up a pump to speed up the process
that was supposedly during the time only one tech was on the job. Previously you referred to the one worker as "he" and when you assisted, it was "we". Are you sure about when the 2nd tech showed up?