@ Cs26kit
in my case ( before trying to save the json) I did check the summary and fortunaifir me, there was no mismatch fron the data entered by me.
When I could not save json, I trued to save as X M L using normal excel "save as" ( since there is no button for saving as X M L). I wanted to save to import it into next avatar of the utility.
But even "save as" did not allow saving as X M L.
Then I got fed up and abandoned the exercise.