Inceptions
You can either hide your listings while away or display a message at the top of your listings. If you choose the message route, eBay will automatically adjust the estimated delivery dates on listings once Time Away kicks in.
Read how it all works here:
The help article says this:
The estimated delivery date will also be automatically updated in the Shipping and Delivery section of your listings, so you don't need to make any manual changes.
They don't specifically spell out anything to do with metrics though it's implied here that if you don't need to make any manual changes, you don't need to make any manual changes.
I always hide my listings when I'm going to be gone and then it isn't an issue. If you want to leave you listings up and be sure about your metrics, you could edit your listings in bulk and add to your handling time...then reverse it when you get back.
You could request a callback from eBay to see what they say, but so many of the CS reps give out incorrect information that I wouldn't feel confident no matter what they said since it's not in writing anywhere...
