Cron skip 1/2 archiving reports (no replies)

I noticed Piwik cron skip one of two archiving reports,
my settings are :

Allow Piwik archiving to trigger when reports are viewed from the browser : No
Reports for today (or any other Date Range including today) will be processed at most every : 3600

Is this normal behavior ?

[2013-03-31 10:05:50] [25ca2436] done: 3/3 100%, 896 v, 3 wtoday, 3 wperiods, 12 req, 47812 ms, no error
[2013-03-31 10:05:50] [25ca2436] Time elapsed: 47.812s

[2013-03-31 11:05:01] [92c0c3d6] done: 0/3 0%, 0 v, 0 wtoday, 0 wperiods, 0 req, 2 ms, no error
[2013-03-31 11:05:01] [92c0c3d6] Time elapsed: 0.002s

[2013-03-31 12:05:48] [2376931c] done: 3/3 100%, 1098 v, 3 wtoday, 3 wperiods, 12 req, 46885 ms, no error
[2013-03-31 12:05:48] [2376931c] Time elapsed: 46.885s

[2013-03-31 13:05:02] [b1209b92] done: 1/3 33%, 115 v, 1 wtoday, 1 wperiods, 4 req, 423 ms, no error
[2013-03-31 13:05:02] [b1209b92] Time elapsed: 0.423s

[2013-03-31 14:05:50] [5e4466ff] done: 3/3 100%, 1412 v, 3 wtoday, 3 wperiods, 12 req, 48688 ms, no error
[2013-03-31 14:05:50] [5e4466ff] Time elapsed: 48.688s

[2013-03-31 15:05:02] [ae0737d4] done: 1/3 33%, 147 v, 1 wtoday, 1 wperiods, 4 req, 421 ms, no error
[2013-03-31 15:05:02] [ae0737d4] Time elapsed: 0.421s