Respawning Units! HELP!

[Mog_Noob]

i have made many custom units of all levels for a hostile enemy but i need it so when a unit dies it respawns after a specific amount of time, also the timing is due to level so lower level units respawn faster, i found how to respawn units but i cant make a condition for level restriction.
Example: i need a level one unit to respawn after 45 second and a level 4 unit to respawn after 60 seconds but i cant specify times for different level creeps

+rep for helping me ploxx x