Proper Cost Splitting - No Random Pennies
When calculating a cost split, the program currently allocates "extra" pennies to random individuals. I would propose that the system carries additional decimals (I think 3 decimals would fix it) in the background and then does final rounding to 2 decimals (ie the penny level) at the very end; ie the summary calculation that tells you who owes what money to whom.
This would cause many problems with the current expectations many people have with Splitwise. For example a $10 expense split among three people could potentially have a non-deterministic outcome guaranteed to be correct and the same across all devices based on how rounding is implemented.