Hi Deepthi,
External numbering is based on the config. If they do not allow external numbering then you cannot upload it using that.
If you want to check it, you can go to OIEN, check whether there is external numbering is checked.
How is your system configured ? How many Equipment categories ?
For example, whether it is same item category for all top level equipments.
I dont see an easy way to update, in case if you need to create sub- equipments, more manual work and excel expert skills required.
Since you need to download the superior equipment numbers and Tag ID, then you need to manually update in load sheet accordingly.
Regards
Terence