It is a common occurrence in Excel for trailing zeros to be dropped. If you encounter this and would like to work with a 14 digit API instead of 10 or 12, you can try using the following formula.
Using this formula will allow you to easily convert all your API's to 14 digits.
=A2&REPT("0",14-LEN(A2))
The formula provided is initially set up to start with the 10 or 12 digit API in cell A2, and it will automatically fill the remaining 2 or 4 numbers with zeros. However, you have the flexibility to modify this to any other cell that holds the API value by changing the 2 references of A2 in the formula to a different cell.
If you copy the formula down, it will automatically update to the next row.