Can I restrict rollover of excess credits to a plan according to its contribution limits?

Yes. When you create a rollover rate, you select the standard rate of the plan, in which you defined the contribution limits.

Example: Your Health Care Reimbursement Account (HCRA) plan has a maximum annual contribution limit of 5000 USD and you want to use that limit to restrict rollovers into the plan. On the Create Rollover Rate page, you select from the Rate for Limits Enforcement list the standard rate of the HCRA plan. During enrollment, any rollover of excess flex credits into the HCRA plan will be restricted to the annual contribution limit set on the rate of the plan.