Replace explicit z-level checks with defines

code/modules/shuttle/on_move.dm

@@ -187,7 +187,7 @@ All ShuttleMove procs go here
 
 /obj/machinery/computer/auxillary_base/afterShuttleMove(turf/oldT, list/movement_force, shuttle_dir, shuttle_preferred_direction, move_dir, rotation)
 	. = ..()
-	if(z == ZLEVEL_MINING) //Avoids double logging and landing on other Z-levels due to badminnery
+	if(is_mining_level(z)) //Avoids double logging and landing on other Z-levels due to badminnery
 		SSblackbox.record_feedback("associative", "colonies_dropped", 1, list("x" = x, "y" = y, "z" = z))
 
 /obj/machinery/gravity_generator/main/beforeShuttleMove(turf/newT, rotation, move_mode)

code/modules/shuttle/shuttle.dm

@@ -391,7 +391,7 @@
 	mode = SHUTTLE_RECALL
 
 /obj/docking_port/mobile/proc/enterTransit()
-	if((SSshuttle.lockdown && (z in GLOB.station_z_levels)) || !canMove())	//emp went off, no escape
+	if((SSshuttle.lockdown && is_station_level(z)) || !canMove())	//emp went off, no escape
 		mode = SHUTTLE_IDLE
 		return
 	previous = null

code/modules/shuttle/supply.dm

@@ -45,7 +45,7 @@ GLOBAL_LIST_INIT(blacklisted_cargo_types, typecacheof(list(
 	SSshuttle.supply = src
 
 /obj/docking_port/mobile/supply/canMove()
-	if(z in GLOB.station_z_levels)
+	if(is_station_level(z))
 		return check_blacklist(shuttle_areas)
 	return ..()
 

code/modules/shuttle/syndicate.dm

@@ -40,7 +40,7 @@
 
 /obj/machinery/computer/shuttle/syndicate/drop_pod/Topic(href, href_list)
 	if(href_list["move"])
-		if(z != ZLEVEL_CENTCOM)
+		if(!is_centcom_level(z))
 			to_chat(usr, "<span class='warning'>Pods are one way!</span>")
 			return 0
 	..()