Well, that works

code/controllers/subsystem/air.dm

@@ -17,6 +17,8 @@ SUBSYSTEM_DEF(air)
 	var/cost_rebuilds = 0
 	var/cost_atmos_machinery = 0
 	var/cost_equalize = 0
+	var/thread_wait_ticks = 0
+	var/cur_thread_wait_ticks = 0
 
 	var/list/hotspots = list()
 	var/list/networks = list()
@@ -57,7 +59,7 @@ SUBSYSTEM_DEF(air)
 /datum/controller/subsystem/air/stat_entry(msg)
 	msg += "C:{"
 	msg += "AT:[round(cost_turfs,1)]|"
-	msg += "TH:[round(turf_process_time(),1)]|"
+	msg += "TH:[round(turf_process_time(),1)],[thread_wait_ticks]|"
 	msg += "EG:[round(cost_groups,1)]|"
 	msg += "EQ:[round(cost_equalize,1)]|"
 	msg += "PO:[round(cost_post_process,1)]|"
@@ -71,7 +73,7 @@ SUBSYSTEM_DEF(air)
 	msg += "HS:[hotspots.len]|"
 	msg += "PN:[networks.len]|"
 	msg += "HP:[high_pressure_delta.len]|"
-	msg += "DF:[max_deferred_airs]"
+	msg += "DF:[max_deferred_airs]|"
 	msg += "GA:[get_amt_gas_mixes()]|"
 	msg += "MG:[get_max_gas_mixes()]|"
 	return ..()
@@ -142,8 +144,11 @@ SUBSYSTEM_DEF(air)
 	if(currentpart == SSAIR_FINALIZE_TURFS)
 		finish_turf_processing(resumed)
 		if(state != SS_RUNNING)
+			cur_thread_wait_ticks++
 			return
 		resumed = 0
+		thread_wait_ticks = MC_AVERAGE(thread_wait_ticks, cur_thread_wait_ticks)
+		cur_thread_wait_ticks = 0
 		currentpart = SSAIR_DEFERRED_AIRS
 	if(currentpart == SSAIR_DEFERRED_AIRS)
 		timer = TICK_USAGE_REAL

code/controllers/subsystem/callback.dm

@@ -4,11 +4,11 @@ SUBSYSTEM_DEF(callbacks)
 	wait = 1
 	priority = FIRE_PRIORITY_CALLBACKS
 
-/proc/process_callbacks()
+/proc/process_atmos_callbacks()
 	SScallbacks.can_fire = 0
 	SScallbacks.flags |= SS_NO_FIRE
 	CRASH("Auxtools not found! Callback subsystem shutting itself off.")
 
 /datum/controller/subsystem/callbacks/fire()
-	if(process_callbacks(null,MC_TICK_REMAINING_MS))
+	if(process_atmos_callbacks(MC_TICK_REMAINING_MS))
 		pause()