Capture today’s effective rate. Write benchmark plus spread exactly as shown in the sanction or latest rate communication.
Map the reset calendar. Note when the benchmark is observed and when your loan actually changes.
Apply an equal upward rate shock. Recalculate EMI or tenure under both structures using the lender’s method.
Apply an equal downward shock. Check how quickly each loan transmits the reduction and whether any request is needed.
Add conversion cost. A switch is worthwhile only if expected savings exceed fees and the remaining loan life is long enough to recover them.
Decision rule: prefer the structure whose benchmark and reset behaviour you can understand and whose downside remains affordable—not simply the one with the lower rate on the comparison date.