Can someone explain the following tkprof summary to me?

=========================================

OVERALL TOTALS FOR ALL NON-RECURSIVE STATEMENTS

call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 27 0.01 0.11 0 2 0 0
Execute 26 0.00 0.00 0 0 0 0
Fetch 24 0.01 0.00 2 107 0 13
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 77 0.02 0.12 2 109 0 13

Misses in library cache during parse: 1


OVERALL TOTALS FOR ALL RECURSIVE STATEMENTS

call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 44 0.00 0.00 0 0 0 0
Execute 44 0.01 0.01 0 0 0 0
Fetch 74 0.00 0.00 3 146 0 41
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 162 0.01 0.02 3 146 0 41

Misses in library cache during parse: 3

27 user SQL statements in session.
44 internal SQL statements in session.
71 SQL statements in session.
************************************************** ******************************
Trace file: qa_s001_3591.trc
Trace file compatibility: 9.00.01
Sort options: default

35 sessions in tracefile.
530 user SQL statements in trace file.
1066 internal SQL statements in trace file.
71 SQL statements in trace file.
17 unique SQL statements in trace file.
966 lines in trace file.

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specifically, how can I have 530 user SQL statements in trace file
and 1066 internal sQL statements in trace file

BUT only 71 SQL statements in trace file?

Aren't they suppose to add up?

Thanks,