Light users should be able to respond to small number of tickets per month or year

Light users should be able to respond to small number of tickets per month or year

I would like to see light users be able to respond to a small number of tickets - something like 5 to 10 tickets per month.  

Use Case: 
We use a help desk to manage requests for client services - the support team are full users.  
We have 3 supervisors/managers that would be light users, but OCCASIONALLY respond directly to clients.  It happens rarely, so it doesn't make sense to have them be full users. 
[For example, our General Manager is a light user, and responds directly to a few (<10) tickets/year]

We've looked at other products that allow "light" users to respond to 10 tickets/month and would like similar functionality in Zoho Desk.

Right now, this problem of allowing light users to respond is a key issue for us.

Having light users be read only is too restrictive and keeps us from using Zoho Desk despite the fact that we use a few other Zoho products.