I am not sure if I understand this report correctly, but I tried the following:
1. Create a new scene
2. Set up some custom tone mapping
3. Save the scene
4. Create a new scene
5. File > Import > Merge, pick the saved scene
6. Make sure I am merging render settings
7. Merge
8. Render - the tone mapping settings from the saved scene are applied
9. Repeat multiple times
I tried this with Corona 9 HF1 and the 16.02 daily build and everything is working fine.
If this report is about something else, please explain how exactly to reproduce it.
Maxscript access to the VFB tone mapping save/load buttons is not available at this time, but we have it reported as a feature request.
(Internal ID=1007269616)