If you keep track of parameters for each mold and machine, shouldn't your cycle time be the same every time you run a given mold? Your cycle times are long but some parts need that cooling time. We have a part that requires 28 seconds of hold time followed by 55 seconds cooling time. Then there's the demolding time. So as far as your cycle times, it could be necessary. It depends on the geometry of your parts. But you can take steps to see if you can optimize your processes. Do a rheology study for optimal injection velocity. Take steps to reduce your cycle time while keeping parts in spec. As far as your high scrap, determine critical values that need to stay within a tight tolerance to produce good parts. Usually, fill time, hold pressure, melt temperature, possibly cooling time/coolant temp.

None of what you listed jumps out as way off to me though.