Listen, the LVL CHG wont honor any altitude constraints. It will only honor the MCP SPEED 
The vertical profile is the thing you sacrifice when you perform a level change. During the descent the autoflight system will command for idle thrust, so the only way for the aircraft to control the speed is by pitch commands...
To have the aircraft follow the vertical profile automaticly, you must be in VNAV mode, period

Level change is used different by different airlines.
Some rarely use it (they go for V/S instead), while other companies insist to use it during climbs/descents that exceeds 1000ft from your current altitude.