Fill in data based on cell change and time?

Ok I have an excel sheet that has data on a tab called "Main". On this tab I have data in columns A:G. The data is as follows, A - Current Date, B - Line in which product comes off of, C - The order number, D - Trailer Number, E - Spot Number, F - Rather its traveling by Rail or Truck, G - Initials of person that worked on it.

So bascially B:F all populate automatically. I just need a macro that auto fills out the date in A when "C" is edited on that line and also when "C" is edited if it could fill out "G" based on the time. Before 2 pm EST the initials should be "Av" and after should be "LC".
Is this possible?

My work does not allow me to upload files so I am unable to upload to show what I am talking about. I will answer any questions I can to help you understand if needed.

Thanks in advance

Anyone come up with anything?