After Oct. 7th patch no experience from most kills . . .
All I can think is, before the servers were restarted for the patch, those mobs were alive a lot longer.
After the server restarted, the mobs had their timers for existence reset, so you got less XP.
Yes, experience at level 80 is important. You get Skill Points for XP at 80 and you need them to craft stuff at the Mystic Forge.
Thanks for the replies. I am learning every day.