Routing Group Counter Selection in Production Order

Hi Guru's,

I have 2 Routing Group Counters,one is Standard(5*********1) & other External(1********5),the system picks up External instead of Standard.

I have checked the Lot sizes & Validity dates, both are same. Also OPL8 & other settings, A Production version is also maintained.

Lot size - 0 to 999999999

Validity - 12/06/2012

Now why is this picking this way ? Any inputs please.