System Profiler Has Duplicate Copies of Apps, why?

I have 2 identical model enterprise disks from WD @7200rpm, 1TB. When I run the Black Magic disk speed test program, the newest disk reports read& write @ 116 mbps and the older disk reports about 126 mbps. That difference is enough to enable the older disk to make HD video transfer speeds, but not the identical new disk.

I started to try to figure why there was such a difference and went to the System Profiler to dig for info. What I saw in both drives under Software then Applications was multiple instances of app files which can be clearly (but small) seen in this screen grab:

Questions:

1) Is this double & sometimes triple instances of the app normal? Look at Chess as an example it has 5 instances, same version, same day, etc.

2) What's going on here? Are these multiple copies of each app saved to the drive?

a) If so, how does one go about deleting the "extra" copies, or are they some Phantom of the Profiler lurking about?

b) If not, why are the entries that are identical in version & date needed? Seems redundant to me.

c) Could this have been produced by the migration assistant?

3) Is this why there is a difference in read & write speed? The older disk, which is faster, has less data on it. The newer disk has more data on, it but only takes up about 300 gig which leaves lots of open space.

Ken