Query count.

+-------------+------+----------------+----------------+----------------+-----------------+
|             | Post | Top-level page | 2nd-level page | 3rd-level page | Post attachment |
+-------------+------+----------------+----------------+----------------+-----------------+
| Trunk       |  26  |      29        |       32       |       39       |       20        |
| Plugin [1]  |  27  |      28        |       33       |       39       |       21        |
| Plugin [2]  |  27  |      30        |       33       |       39       |       21        |
+-------------+------+----------------+----------------+----------------+-----------------+

[1] Using "could try to be a bit smarter and get an ID now" part
[2] Not using "could try to be a bit smarter and get an ID now" part

Obviously your experience may differ due to other factors, e.g. navigation menu, but relative
numbers between the different setups should remain the same (i.e. +1 for both variations of the
plugin on a post compared to trunk).