Difference between pctchg and percent when calibrating CN2 in SWAT+ Toolbox 4.0.0

[Antonio Dotto]

Good morning, I hope you are all doing well!

I am using SWAT+ Toolbox 4.0.0 and have encountered a significant difference that I haven't been able to understand. When entering calibration parameters individually in the Toolbox, the change type appears differently than when I add the same parameter via a Parameter Set.

In the Parameter Set:

Replace is converted to absval;
Relative Value is converted to abschg;
Percent appears as percent.

The problem is that the simulation results are vastly different. For example:

pctchg → CN2 resulting in approximately 29 → NSE = 0.83, but with a highly inconsistent water balance and several warnings;
percent → CN2 resulting in approximately 69 → NSE = 0.80, but with a consistent water balance and no warnings.

Why does applying the same parameter—and theoretically the same method—produce such different CN2 values ​​and, consequently, different hydrological results?

I would also like to know if Replace → absval, Relative Value → abschg, and Percent → pctchg are the correct mappings between the Toolbox options and the change types used by SWAT+.

Is there any difference in how these parameters are applied when entered individually versus via a Parameter Set?

Finally, which file should I check (e.g., calibration.cal or another file) to confirm exactly how the Toolbox is applying CN2 during calibration?

Thank you!