Custom Fields Limit Per Field Type Not Allowed

Custom Fields Limit Per Field Type Not Allowed

I'm aware of the custom field limits per type;

https://www.zoho.com/crm/help/customization/custom-fields.html#Custom_Field_Table

Is the total limit cumulative or per field type? If I have 25 custom string fields and I want to add an additional integer custom field it doesn't allow me to and says that I reached my limit. Based on the chart I should be able to add an integer custom field since the limit is 15 and I haven't used any yet. Is this how it's supposed to work?