I changed the script a bit, so that the txt file is not getting
recreated every time.
It gives:

[stefan@localhost ~]$ python ziptest.py 
Start 10:15:05
ZIP stored mtime: (2008, 6, 29, 10, 15, 4)
Original mtime: (2008, 6, 29, 10, 15, 5)
Duration 0.00438690185547
Stop 10:15:05
------------------------------
Start 10:15:06
ZIP stored mtime: (2008, 6, 29, 10, 15, 4)
Original mtime: (2008, 6, 29, 10, 15, 5)
Duration 0.00189399719238
Stop 10:15:06
------------------------------
Start 10:15:07
ZIP stored mtime: (2008, 6, 29, 10, 15, 4)
Original mtime: (2008, 6, 29, 10, 15, 5)
Duration 0.00167894363403
Stop 10:15:07
------------------------------
Start 10:15:08
ZIP stored mtime: (2008, 6, 29, 10, 15, 4)
Original mtime: (2008, 6, 29, 10, 15, 5)
Duration 0.00195598602295
Stop 10:15:08
------------------------------
Start 10:15:09
ZIP stored mtime: (2008, 6, 29, 10, 15, 4)
Original mtime: (2008, 6, 29, 10, 15, 5)
Duration 0.0136680603027
Stop 10:15:09
------------------------------
Start 10:15:10
ZIP stored mtime: (2008, 6, 29, 10, 15, 4)
Original mtime: (2008, 6, 29, 10, 15, 5)
Duration 0.00206613540649
Stop 10:15:10
------------------------------
Start 10:15:11
ZIP stored mtime: (2008, 6, 29, 10, 15, 4)
Original mtime: (2008, 6, 29, 10, 15, 5)
Duration 0.00191879272461
Stop 10:15:11
------------------------------
Start 10:15:12
ZIP stored mtime: (2008, 6, 29, 10, 15, 4)
Original mtime: (2008, 6, 29, 10, 15, 5)
Duration 0.00196504592896
Stop 10:15:12
------------------------------
Start 10:15:13
ZIP stored mtime: (2008, 6, 29, 10, 15, 4)
Original mtime: (2008, 6, 29, 10, 15, 5)
Duration 0.00182104110718
Stop 10:15:13
------------------------------
Start 10:15:14
ZIP stored mtime: (2008, 6, 29, 10, 15, 4)
Original mtime: (2008, 6, 29, 10, 15, 5)
Duration 0.0369889736176
Stop 10:15:14
------------------------------