Three years: 30,000 * 5.22% * 3 = 4,698 yuan.

(30000+4698) * 5.22% * 3 = 5433+0 yuan.

4698+5433.75438+0 =10/31.71yuan.

10368-10131.71= 236.29 yuan.

Six years is suitable, with a difference of 236.29 yuan.