Thank you all for that information. There are ways of resolving the timestamp in a decentralized manner. when conducting the comparison of the size of the proof of work, each submitted proof of work will have an associated timestamp. Take the average and use that as the timestamp for the longest.  There are also methods of synchronizing the network clock, using the clocktime of participants.

From an analytics standpoint accurate time measurements are very important.

To the second part:

Where can I find the equations that are used to calculate difficulty (base 10 for dummies please) and network hash rate for each block?

Thanks again