UI7 Scheduling Problem

I have several potted plants that are watered with a setup of pails in which I place water and a submersible pimp. I then route the water to the plant via tubing on a set schedule - the 8th 18th and 28th of each month. With UI5, I was able to specify the time that the pump turned on and shut off down to the second e.g. I created one scene to turn the pump on at 11:00:00 AM and another to turn the pump off at 11:00:23 AM so that in this example the plant was watered for 23 seconds. This is important since too much time would cause the water to overflow and get onto the furniture and too little would kill the plant.

With UI7, I wanted to modify one schedule and turn a pump off 3 seconds later and found that I can only modify hours and minutes but I can not change the seconds. It is important to note that the pump is indeed running for the seconds specified (which apparently transferred correctly from UI5). What am I doing wrong or what can I do to fix this?

Think I might have found a work-around for the lack of the ability to select seconds when setting up a scene-schedule; and that is to use the delay (rather than immediate feature when designating the time) - if, for instance, I want the pump to run 23 seconds, I can create a schedule to start it at 11:00 AM and designate a 23 second delay and then in that same scene I can turn the pump off at the end of the delay. This should give me the 23 seconds than I am trying to achieve, in this example. I tested this approach and it works well.