Not sure if you've figured this out yet or not. If not, my recommendation is to put dev report suites in the account section of DTM and use the s_code editor to create logic that decides which report suite to send the data to. In my experience, the s.account variable in s_code overwrites the items defined in the Tool's Production/Staging Account/Suite.
I've also noticed that developers seem to get confused by (or simply forget to) remove the -staging.js in the <head> embed code for DTM. To get around this, I've started only giving developers the production embed code. I then use the s_code editor to send the data to the proper report suite (based on URL/domain).