I only play slots (NO video poker). Last year, if I earned in LAS (say) 2000 tier credits in one day, my reward credits would be close to 4000; this year, I get close to 2000. [I generally only play penny slots, every now and then I play $1 slots (actually a "sphinx" game)--this seems to generate higher RC for the same amt of TC (as with pennies).]
Atlantic City, for 2000 TC, never gave much more than 2000--but there are lots of multiplier days (which LAS rarely has).
PS: Generally (for AC), holidays have (big) multiplier days. I seem to remember Jan. 1, 2013 as being over 20x.^
PS(PS):Right now, in AC, every Thursday (through the end of Aug.) is a 10x day.