Great info and thanks for sharing! Love the part and the code for cloning an EEPROM!
I will note that most likely this guy just had a bad EEPROM chip. He states "due to constant rewrite of current position". Unless he was constantly changing the clamps on his dish or something, there is no constant rewrite of the current position. This is often a misconception about EEPROM chips. Reading the chip is not the same as writing. You can perform many, many more reads than you can erase/writes.
When you move your dish to a certain position when you are first setting it up and hit save, that is a write. No one changes their dish parts around that much, that they are constantly, daily writing. Even if he did 100 writes a week it would take 19 years to hit 100K writes. Just telling your dish to go to 99W for example and the vBox looks up what 99W is...this is just a read.
Being though how an EEPROM works internally, it is most likely that they got the cheapest ones they could find and the manufacturing process, made them not to be the best EEPROM. Also it could have been as simple as a cold solder joint and changing out the EEPROM chip fixed that.
Going a step further according to the data sheet on that chip, if done right, it should have 1,000,000 erase/write cycles before data corruption; it also has a data retention rate of >200 years... So you can do the math on that.