I am trying to find out difference between two days "xx years xx days xx hours xx minutes" format. My start date is in A column and end date is in B. Calculating difference in C column.

I am using B1-A1 formula in C column and using custom format "yy" years "dd" days "hh" hours "mm" minutes" in C column. It works fine if the start and end years are different. But if it is same, C column reporting incorrect years and days. (showing as 99 years and 30 days).

How to fix it ?