It would be helpful to establish a time range for taking measurements. I've had the problem where I took an initial measurement at 1:00 PM on a particular day. The following day, I had to take the measurement before 1:00 PM, because if I tried to do it after that time, it wouldn't allow it.
It would be helpful if it allowed me to take measurements throughout the following day or if I could set a specific time frame for taking measurements.