Also, the northern tier of sections and the western tier of sections in a township are not always 640 acres. Those sections may differ slightly due to the correction for the curvature of the earth. The clue that you are not at 640 is the use of the words Lots 1 and 2 as those are the ones that are different.
For many states you can find out the acreage on the BLM website.
Now Zoom into section 4 and you will get the odd lots. Lot 1 is 40,81 and lot 2 is 40.83 acres. As Pete said, the S2 NE4 is 80 acres (blank on the map since it is “normal”) and the E2 SE4 is also “normal” at 80 acres. Original gross total is 241.64 acres which is accurate. Your percentage would be determined by how much of that she actually owned and then what she passed to each heir.
