Warning Currently not released, still in beta. Feel free to try it out & to submit PRs.
"Relative Splits" is a work-in-progress Openplanet plugin that displays the difference between two individual checkpoints when compared to your personal best run. For instance, if you have a negative split of -0.500 on Checkpoint 1 and -0.400 on Checkpoint 2, the plugin would display the resultant loss of 0.100. If this piques your interest, feel free to try it out and contribute to the source code.