Question about using “PreprocessingVariationalEquation” to generate dynamic orbits

[MingtaoZHU]

Dear GROOPS developers,
I have recently been studying the impact of surface hydrological changes (such as floods) on the GRACE-FO satellite orbit. My approach is to calculate the reference orbit for July 2020 based on the Background models for June 2020. The settings in the Background models are the same as in the "scenarioGraceGravityfieldRecovery" example. The only difference is that the Earth's gravity force is calculated by combining the JPL monthly L2 solution (degrees 0–96) with the high‐degree (97–200) portion of GOCO06s for a full consideration of global gravity field before the flooding occurrence (referenced from Li et al., WRR, 2024).
I would like to ask if there is any need to perform PreprocessingVariationalEquationOrbitFit and PreprocessingVariationalEquationSstFit when using 020groopsVariational.xml, because my goal is to find the difference between the reference orbit and the actual orbit, which just reflects the orbital perturbations caused by changes in the hydrological environment.