Hi lookandbuyme,
Based on what I observed with respect to your listings that do not show your Domestic Handling Time on eBay, I do not feel that it should be necessary to revise them. As I mentioned, I was able to confirm that eBay already has your Domestic Handling Time of 1 day on file for your listings I reviewed which exhibit this problem and it is just not being displayed for some reason.
I am not familiar with what you may see when you visit the eBay Revise your Item form for these items but, when I requested the details of each listing through the eBay API, the details that were returned included the appropriate Domestic Handling Time.
I am also not entirely sure what caused you to receive the error you mentioned when attempting to revise the Domestic Handling Times of your listings in bulk through your Auctiva account, but I feel it is most likely indicative that the system timed out during the request.
Assuming that is the case, I suspect you will most likely be able to work around the error by reducing the number of listings that you are attempting to revise at one time. I'm just not sure that revising your listings will resolve the problem given the information you are looking to add is already in their system.
If you need further assistance with this, please file a support case and we will continue working with you through that medium. Going into this any further will require discussing specifics from your account and it is preferable to do that through the support system.
-Mike