HP 48 ram card from Ebay: why would self-test be required?

[arborist]

This (unofficial) HP 48 card is sold with surprising instructions and there are two things I don't understand:

1. Why do they ask to go through the port ram test (On + D, then "up")? Does this test do something useful to reset the card? Given the instructions, it seems like one can expect this to fail at first but then eventually succeed. Why would that be?

2. They say the card only works in slot 2. After step (1), wouldn't it work also in slot 1, with only 128kB visible?