Sort of. On the other hand, it was quite common in 3e to "overload" encounters - I know that I, for one, almost never used encounters below the PCs' level, but quite often above, in order to compensate for action points and other power creep, as well as for various classes being able to "nova". Pretty sure I've seen a Design & Development article to that effect as well.
Anyway, so while the intention in 3e might have been to have 13 1/3 encounters per level, the truth is probably closer to 7-10.