By “drop rate”, I can only assume you mean the amount of stamina/credits dropped at successively higher levels of port. A simple check of the game shows that they do, indeed, increase. If that’s not what you meant by “drop rate”, then the first sentence of your comment is as off-topic as your second.
RNG determines how much stamina one gets, restricted to a range between a minimum value and a maximum value, both of which are easy to calculate based on the information the game gives you. And since Pipsqueak measured just the maximum amount, RNG is irrelevant to the discussion.