Maybe the receipt is too small on the flatbed for the scanner to sense it. How about placing a blank letter-sized sheet of paper behind the receipt....
I wouldn't want to replace the new with the old myself. There are likely going to be inconsistencies due to versioning. You could move the old stuff...
In parts of the world with power limitations, most people use laptops rather than using a full desktop. That way they have a built-in battery backup...