Timer Rewind Script not counting time correctly

My question concerns a quickly coded effect I made for a game jam a few days ago.

This script, countDown.cs, can be found at the following link, along with the entirety of the project. https://github.com/htw6174/LaborJam/blob/master/LaborJam/Assets/Scripts/countDown.cs

The purpose of this script, which was just attached to a Text field on the player's HUD was to display the current time remaining to fulfill the objectives in the game. Upon failure (if (locTime <= 0)), the player would be rewinded to the beginning.

I keep experiencing a bug where when locTime reaches 0, it begins adding time back up, relative to the delay between recording frames and the delay between replaying frames, both set in rewind.cs which can be found here: https://github.com/htw6174/LaborJam/blob/master/LaborJam/Assets/Scripts/rewind.cs

It usually rewinded the time up to 1.3 times the starting time, and I have a feeling I am doing something wrong with the timing. Currently, I realized that the error a fairly reliable time off, so I was able to approximately correct for the bug by just multiplying SubtractingTime by a scalar (7.0f/3.0f), but it feels bad, and also might not work for all people playing the game.

Can anyone help me understand why this is off? Ideally the timer would start at 5 minutes, and run down to 0:00, then trigger rewind, making the rewind play, and counting back up to 5 minutes in the appropriate step size (SubtractingTime).

The entire project can be viewed/downloaded here: https://github.com/htw6174/LaborJam