Feature Request in Zoho Books : Tracking Inventory for Service Items

Feature Request in Zoho Books : Tracking Inventory for Service Items

At the moment, ZOHO Books don't allow to track inventory of Service Items (I just talked with customer care executive for confirmation).

MY PROBLEM:
I resell services Digital Signatures Certificates ( SAC ‐ 998319) and other similar services, I purchase certain quantity from vendor and resell them with variable prices. Suppose I purchased 200 certificates @ 300. 

How I can keep track of quantity sold for services ?? 

Customer Care Executive Suggested me REPORTING TAGS: 
I tried reporting tags but they don't much useful coz it don't show total quantity & invoice level quantity.

So I request to Add INVENTORY FEATURE for Services in ZOHO Books

Regards
Bk Kalia