Hi @wei2912,
You can set the rollover amount (prior amounts) using the short cut commands in the adjust cell on the Budget dashboard itself. Just type in r=[amount] you want to use as the starting balance for the category. The Analyze Budgets History shouldn’t wipe it out.
Documented here under “Monitoring and Managing Your Budget > Key Workflows > Adjusting Budgets”.
Let me know if that doesn’t help.
Heather