How to add total time spent value via API

Hi

I am using the time tracking app addon from Zendesk

https://www.zendesk.com/in/marketplace/apps/support/35111/time-tracking/

I really like the way the total time spent is tracked there. I am in the middle of a move from old system to zendesk ticketing system. In this partway move I need to use the old system to enter tickets, but a copy needs to be entered here in zendesk. 

There lots of blockers preventing me from creating in zendesk ticket in the first place. 

I am able to create new tickets via the API but unable to update Total time spent value.

I have reached out to support, and they requested me to raise a post here in the community. 

I found a similar post but no reply there
How can I get the Total time spent value from time tracking App through API? – Zendesk help

Can anyone help me solve this problem? or provide an alternate way to track time spent working on a ticket.