Updating weights would normally happen out in the mail
room or warehouse, after the shipment has been fully picked and packed.
The mail room/warehouse needs only a PC with ShipRush running in Stand
Alone mode (the accounting or CRM application is not needed). If the PC
has a scale configured with ShipRush, that helps, but is not required.
Shipments processed with the Scale Later option can be managed in the View Shipments area. Note how this shipment has a Yes in the Must Scale column:

Don't see the Must Scale column in your View Shipments?
Just right click anywhere on the list area and select Customize Columns.
Then drag the Must Scale item from the column list onto the actual package
list. Done!
Parcels marked Yes in the Must Scale column will not
upload to UPS and must not be tendered to UPS for shipment. If such a
parcel is shipped it will likely lead to an excessive bill.
To update the weight and (optionally) the dimensions, just right click on the shipment and select Update Weight (or select the package and press Ctrl-Alt-U. You get the Update Weight form:

Simply enter the weight and (optionally) dimensions, and press Update Package.
The Must Scale column is now empty, and notice that the Weight column says '3' (the weight that was set for this parcel):

That is it. We have just updated this parcel, and it will upload when End of Day is next done.
Simply go through the list of parcels with the Must Scale showing 'Yes' and update the weights. Then press the Close Day button and you are done!
The values on the Update Shipping Weight form can be set using a bar code scanner.
Next: Setting Weights and Dimensions Automagically