When the VM is "Stopped", the OS has essentially been turned off but the IP address is retained and it can be quickly started again.  Azure will continue to bill for the VM until the instance is fully shut down. 

Only when VM status is "Stopped(Deallocated)" will Compute charges will not be incurred.

For more information please see: Difference Between the States of Azure Virtual Machines: Stopped and Stopped (Deallocated)