App Engineの信頼性は95%程度？

最近、App Engineで下記のようなエラーをよく見かける気がします。

500 10871ms 0cpu_ms 0kb AppEngine-Google; (+http://code.google.com/appengine)
Request was aborted after waiting too long to attempt to service your request. This may happen sporadically when the App Engine serving cluster is under unexpectedly high or uneven load. If you see this message frequently, please contact the App Engine team.

手元のアプリでは1時間毎にcron、5分毎にTaskQueueを走らせていますが、ところどころで欠損が見られます。

6/6〜6/9に発生した500エラーを表にしてみました。1日当たり312リクエスト*1が実行されるはずなので、およそ5〜7%程度が欠損していることになります。こんなもんなのかな？

PST (-7)	JST (+9)
2010/06/09 6:03:38	2010/06/09 22:03:38
2010/06/09 6:03:38	2010/06/09 22:03:38
2010/06/09 1:48:27	2010/06/09 17:48:27
2010/06/08 22:48:19	2010/06/09 14:48:19
2010/06/08 21:08:15	2010/06/09 13:08:15
2010/06/08 18:33:07	2010/06/09 10:33:07
2010/06/08 15:02:59	2010/06/09 7:02:59
2010/06/08 14:07:55	2010/06/09 6:07:55
2010/06/08 11:37:38	2010/06/09 3:37:38
2010/06/08 11:09:36	2010/06/09 3:09:36
2010/06/08 11:07:36	2010/06/09 3:07:36
2010/06/08 10:37:35	2010/06/09 2:37:35
2010/06/08 9:57:33	2010/06/09 1:57:33
2010/06/08 9:27:33	2010/06/09 1:27:33
2010/06/08 7:32:12	2010/06/08 23:32:12
2010/06/08 6:52:08	2010/06/08 22:52:08
2010/06/08 6:17:02	2010/06/08 22:17:02
2010/06/08 2:46:57	2010/06/08 18:46:57
2010/06/08 0:11:49	2010/06/08 16:11:49
2010/06/07 22:51:47	2010/06/08 14:51:47
2010/06/07 22:01:36	2010/06/08 14:01:36
2010/06/07 19:41:28	2010/06/08 11:41:28
2010/06/07 19:36:27	2010/06/08 11:36:27
2010/06/07 18:51:26	2010/06/08 10:51:26
2010/06/07 18:01:17	2010/06/08 10:01:17
2010/06/07 16:18:05	2010/06/08 8:18:05
2010/06/07 16:16:05	2010/06/08 8:16:05
2010/06/07 15:51:05	2010/06/08 7:51:05
2010/06/07 15:41:04	2010/06/08 7:41:04
2010/06/07 15:16:00	2010/06/08 7:16:00
2010/06/07 15:11:00	2010/06/08 7:11:00
2010/06/07 13:25:50	2010/06/08 5:25:50
2010/06/07 12:55:48	2010/06/08 4:55:48
2010/06/07 12:03:47	2010/06/08 4:03:47
2010/06/07 11:13:45	2010/06/08 3:13:45
2010/06/07 9:53:43	2010/06/08 1:53:43
2010/06/07 8:48:31	2010/06/08 0:48:31
2010/06/07 6:13:13	2010/06/07 22:13:13
2010/06/07 6:03:13	2010/06/07 22:03:13
2010/06/07 5:53:13	2010/06/07 21:53:13
2010/06/07 5:45:13	2010/06/07 21:45:13
2010/06/07 5:43:13	2010/06/07 21:43:13
2010/06/07 3:23:09	2010/06/07 19:23:09
2010/06/07 2:28:07	2010/06/07 18:28:07
2010/06/07 1:33:05	2010/06/07 17:33:05
2010/06/06 18:52:47	2010/06/07 10:52:47
2010/06/06 18:31:05	2010/06/07 10:31:05
2010/06/06 18:30:42	2010/06/07 10:30:42
2010/06/06 18:29:47	2010/06/07 10:29:47
2010/06/06 18:27:47	2010/06/07 10:27:47
2010/06/06 15:57:42	2010/06/07 7:57:42
2010/06/06 15:42:42	2010/06/07 7:42:42
2010/06/06 10:37:19	2010/06/07 2:37:19
2010/06/06 10:07:18	2010/06/07 2:07:18
2010/06/06 2:41:50	2010/06/06 18:41:50