License Renewal with Days Remaining on Current

Does Mobile Security operate in the same manner as Internet Security when renewing a license with time still remaining on the current license?  NIS only assigns the days remaining for the new license/activation although you can call or go online to have someone manually add the “lost” days back for you.  As a result I typically just wait for the product to expire before typing in the new activation code.  Not willing to do any automatic renewal.