I have four weather stations, each in a separate tab in a spreadsheet. I defined the columns for the first weather station. For the 2nd, 3rd, and 4th weather station, I copied the table definitions from the first and saved the template. But these sheets remain undefined when I open the file again. In fact those sheets were "unchecked", not included in the mapping.
I had to redefine each column in each sheet to get around this.