The limit on the sub-category will only impact the profit and loss statement. The same can be increased by following the below steps:
The maximum by default is 33, say you need to increase the same to 80.
1. Unprotect the Profit & Lost sheet using the password as "indzara"
Read here to know more: How to unprotect sheets?
2. Unhide the column A and B, by right-clicking on the column C header, as shown:
3. Select any two numbers in column A and drag down till 87 for 80 subcategories.
4. Then select cells B4 to O98 (Specified O98 considering you added numbers up to to 87 in column A.)
5. Press CTRL+D to duplicate the formulas.
6. Hide columns A and B and hide the sheet to ensure the formulas are not deleted or modified accidentally.