What I'd like to know is: Is the number of 10 encounters per day similar to the 13 CR = EL encounters of 3E, or did they also take into account a few more difficult encounters?
For the record: If we are supposed to send 4 PCs vs. 4 NPCs in an average ecnounter, this would boil down to 100 XP per person (by the published XP values for 1st level NPCs). So, to get to 2nd level with 10 encounters, you'd need 1.000 XP.
2nd level PCs would then require you to get 1.250 XP, 3rd level PCs 1.500, 4th level PCs 1.750, and 5th level PCs. 2.000 XP. Leaving us with an XP table that looked something like this
Level 2: 1000 XP
Level 3: 2.250 XP
Level 4: 3.750 XP
Level 5: 5.500 XP
(...)
Errors in this table:
(1) Actually, the standard assumption is 5 PCs vs 4 NPCs, at least according to the preview books, IIRC. This might indicate more then 10 encounters per level, or would allow us to stray in a few more difficult encounters.
(2) My XP estimation for NPCs might be slightly off. I think they match with what I have seen so far, but I am not 100% confident.