"onstat -g arc" reporting backup levels

Below is the output from "onstat -g arc" (Informix 7.31 on AIX). Can anyone tell me why it's interesting to know that I have an older incremental backup than my full backup? You can see that dbspaces atg29 and atg01 have a full backup from May 30 and a incremental backup from May 29. The same was reported for the rootdbs before I did a "onbar -b -L 0" (The backup process is currently backing up atg29 and atg01). I can't understand why the scheduled full backup from May 30 didn't clear the incremental backup entries as the command line invoking of "onbar -b -L 0" just did for the rootdbs. Dbspaces - Archive Status name number level date log log-posit rootdbs 1 0 05/31/2003.13:53 592 0x15f018 atg29 3 0 05/30/2003.08:12 553 0x105018 1 05/29/2003.20:57 549 0x11f018 atg01 4 0 05/30/2003.08:12 553 0x105018 1 05/29/2003.20:57 549 0x11e018