بسم الله الرحمن الرحيم
If the rate of interest is decreased or increased due to some risk or without it, then also it does not make the interest based dealing lawful.
Whatsoever amount the bank gives you as interest after you deposit five thousand rupees each month it shall be interest and this will be considered interest based dealing. Thus it is haram to earn benefit in this way.
Allah knows Best!
Darul Uloom Deoband