Adarsh,
Application user licenses are measured in PRD systems, as the end product developed(DEVELOPMENT system),tested(Quality system) is moved to PRD and End users will login in PRD to work on them(or use them).
SAP will verify whether you have created 70 Application users or more than that through Measurement report.
For Developer User information.
SAP will ask you to provide system measurement report from DEV system.
Because any development or change to SAP objects are performed mostly in DEV system.
If multiple user ids used for changing SAP objects through developer keys. in that case those users who are involved in changing the objects with developer keys will be treated are developers.
In your case you should be using single user for Changing the SAP objects.
Regards
Anand