When ever a text box is double clicked it runs a procedure for that texbox.
This line determines the cell in the data sheet to either pull the value from or add the new value to.
in this case the 16 was a different number, so when you submitted it, it went to the wrong cell. So another part of the code would pull a different cell value in.
The .offset(0,16).address means if the active cell was A2 then it would be locating the address of the cell on the same row but 16 columns along.
Hope that helps.
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