This is a bug that has been around for many, many years: it is impossible to type specific values into the Time Remap field in the Timeline panel.
Steps to Reproduce:
1. Drop some footage into a comp
2. Right-click it and 'enable time remapping'
3. Add a keyframe or two
4. Click on the timecode of one of the keyframes and type in a new value. Or press the arrow up/down keys.
Either nothing changes or the timecode changes to something other than the value typed in.
The timecode should be whatever was typed in. Or it should get nudged up/down by 1 frame when pressing the arrow keys.
Scrub the value to get a kinda-accurate figure in there.
Have something to add?