It's more or less random.
For example, my Allan Dubois is still 10, while the OPs is now 9
Not true, read again.  The other poster is guessing that Dubois will fall to 9 soon.  (With no actual basis for this guess).
All Allan Dubois out there will drop at that same time.  Currently, all of them are 10s.
My reading comprehension issues aside (I fail hard), it IS random.
Not all of them will fall the same week.
NO ONE at this table ordered a rum & Coke 
 Charles: Penn has some good people 
 A CT? Really? 
 Any two will do 
 Any three for me 
 Any four will score 
 Any five are live