PO condition value is ZERO after MIGO 101 & 105.

Dear Experts,

We are created one freight condition type  "ZTFR"  with access sequence but in our some pos it is showing inconsistent data. one example..

We update this condition in August with validity period 01.08.2015 to 31.12.9999...

We created PO in OCT and received data and ZTFR update in table "EXBZ",but in November our PO shown Zero Value against this condition type and we are not able to post value against this condition type because values zero in PO now.

We already checked No updated/No Change in this condition with FV11, FV12 and we are not able to update this condition in PO also.and no found any changing in PO display change.As we now if we received migo 101 or 105 than no condition update in PO also.

Could any body suggest how we can trace we is fault in this condition...

Regards

Rajesh