You are able to update products from Dropship Zone API with Stock Sync. Just choose on Dropship Zone API template after choosing to update existing products in your store. 

1. Go to Setup New Feed > Choose Update existing products.

2. Choose or search for Dropship Zone API template.

3. Then, you need to fill up the email and password.

4. After that, you can click Next to the field mapping section.

These are the available fields that can be updated with Stock Sync. 

product titletitle
5. Once checked the field mapping section, you can set anything that you need in advanced setting. If you do not want to do any changes, you can click Next and finish the setup feed.

6. You can start the process to update the products.