So true in TX! And confusing if you don’t stay on top of it. Good to do an annual check of all of your wells.
OK is a bit more stable as most wells report from the meter at the wellhead and stay the same. They keep their API unless they drill a sidetrack and then they will add four more digits onto the end such as 0001 or 0002 for a second sidetrack. Occasionally, the PUN number will change with a gathering of several wells into one meter, so keep that number in your spreadsheet as well. Also good to have a column for your owner ID and a column for your property ID listed on the statement. Those can change over time as operators change. The property ID is how many of the owners identify a well for internal accounting purposes. I have several operators that have multiple owner IDs for me. They have bought other acreage and each set of purchases gave me a new ID. Lots to keep track of!