GorgeousGeorge

If you have it configured to shut down ASAP and it manages to do so then you don't need to expand your configuration. Splitting the load between the units will increase the runtime per unit, but it would be unnecessary in your case as you're not seeking any run time. We have a Smart UPS 1000 SUA1000 that runs several machines and is instructed to shut everything down as soon as the power goes out. In another part of the office we have the phone system configured to run as long as possible on a SUA1000XL with an external battery pack. For the machines, it wouldn't make sense for us to upgrade to a bigger unit or even split the units as we don't need the run time at all. However, on the phone system we want as long of a runtime as possible. The key is to size things properly in hopes of having the most cost efficient configuration. If you oversize, it costs more up front and more in the long run due to increased maintenance.

If the unit doesn't have over 80% load on it and you're satisfied with the run time, you'd be good to go. If you're unhappy with the runtime, feel it's too short or don't have enough time to safely shut down, you need to get a different UPS. Sizing UPSs is tricky, you want enough but not too much, if you have too much it costs longer in the long run as maintenance is more expensive. How often do you have power outages?