Unable to enable 'Sales account' on Manage item

Summary

Sales Account grayed out at the Master Level and not getting enable

Content

Hello Team,

I am trying to enable the 'Sales Account' field in the Specifications for OM attributes in an item. I crossed the setup via 'Manage Operational Attributes % and found it is already selected at 'Master Level'.

Tried to changed the control at ORG level, it works however at item's MASTER level it is showing as grayed out only. Please suggest what I need to do, to enable it Master control?

 

Appreciate your quick response.

 

Version

R13 - 19B