Index: binaries/data/mods/public/simulation/components/BuildingAI.js
===================================================================
--- binaries/data/mods/public/simulation/components/BuildingAI.js
+++ binaries/data/mods/public/simulation/components/BuildingAI.js
@@ -73,12 +73,7 @@
 
 BuildingAI.prototype.OnDestroy = function()
 {
-	if (this.timer)
-	{
-		let cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
-		cmpTimer.CancelTimer(this.timer);
-		this.timer = undefined;
-	}
+	this.StopTimer();
 
 	// Clean up range queries
 	let cmpRangeManager = Engine.QueryInterface(SYSTEM_ENTITY, IID_RangeManager);
@@ -96,6 +91,13 @@
 	if (msg.component != "Attack")
 		return;
 
+	// Restart the timer if the attack repeat time has changed
+	if (this.timer && msg.valueNames.indexOf("Attack/" + attackType + "/RepeatTime") != -1)
+	{
+		this.StopTimer();
+		this.StartTimer(0);
+	}
+
 	this.targetUnits = [];
 	this.SetupRangeQuery();
 	this.SetupGaiaRangeQuery();
@@ -203,7 +205,7 @@
 		this.StartTimer();
 };
 
-BuildingAI.prototype.StartTimer = function()
+BuildingAI.prototype.StartTimer = function(offset)
 {
 	if (this.timer)
 		return;
@@ -215,8 +217,20 @@
 	var cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
 	var attackTimers = cmpAttack.GetTimers(attackType);
 
+	// Rather than figure out the correct offset when resetting the timer, use an estimate of half of the repeat time
 	this.timer = cmpTimer.SetInterval(this.entity, IID_BuildingAI, "FireArrows",
-		attackTimers.prepare, attackTimers.repeat / roundCount, null);
+		offset === undefined ? attackTimers.prepare : attackTimers.repeat / roundCount / 2,
+		attackTimers.repeat / roundCount, null);
+};
+
+BuildingAI.prototype.StopTimer = function()
+{
+	if (!this.timer)
+		return;
+
+	let cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
+	cmpTimer.CancelTimer(this.timer);
+	this.timer = undefined;
 };
 
 BuildingAI.prototype.GetDefaultArrowCount = function()
@@ -276,12 +290,7 @@
 {
 	if (!this.targetUnits.length && !this.unitAITarget)
 	{
-		if (!this.timer)
-			return;
-
-		let cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
-		cmpTimer.CancelTimer(this.timer);
-		this.timer = undefined;
+		this.StopTimer();
 		return;
 	}
 
Index: binaries/data/mods/public/simulation/components/UnitAI.js
===================================================================
--- binaries/data/mods/public/simulation/components/UnitAI.js
+++ binaries/data/mods/public/simulation/components/UnitAI.js
@@ -177,6 +177,10 @@
 		// ignore
 	},
 
+	"ValueModification": function(msg) {
+		// ignore
+	},
+
 	// Formation handlers:
 
 	"FormationLeave": function(msg) {
@@ -1935,13 +1939,14 @@
 
 					// If the repeat time since the last attack hasn't elapsed,
 					// delay this attack to avoid attacking too fast.
-					var prepare = this.attackTimers.prepare;
+					let prepare = this.attackTimers.prepare;
+					let cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
 					if (this.lastAttacked)
 					{
-						var cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
-						var repeatLeft = this.lastAttacked + this.attackTimers.repeat - cmpTimer.GetTime();
+						let repeatLeft = this.lastAttacked + this.attackTimers.repeat - cmpTimer.GetTime();
 						prepare = Math.max(prepare, repeatLeft);
 					}
+					this.lastAttacked = cmpTimer.GetTime() + prepare - this.attackTimers.repeat;
 
 					this.oldAttackType = this.order.data.attackType;
 					// add prefix + no capital first letter for attackType
@@ -2074,6 +2079,27 @@
 						this.WalkToHeldPosition();
 				},
 
+				"ValueModification": function(msg) {
+					// Restart the timer if the attack repeat time has changed
+					if (msg.data.valueNames.indexOf("Attack/" + this.oldAttackType + "/RepeatTime") != -1)
+					{
+						let cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
+						let cmpAttack = Engine.QueryInterface(this.entity, IID_Attack);
+						let attackTimers = cmpAttack.GetTimers(this.order.data.attackType);
+
+						let oldRepeatLeft = this.lastAttacked + this.attackTimers.repeat - cmpTimer.GetTime();
+						let scale = attackTimers.repeat / this.attackTimers.repeat;
+						let repeatLeft = Math.round(scale * oldRepeatLeft);
+
+						this.attackTimers = attackTimers;
+						this.lastAttacked = cmpTimer.GetTime() + repeatLeft - this.attackTimers.repeat;
+
+						this.StopTimer();
+						this.StartTimer(repeatLeft, this.attackTimers.repeat);
+						this.SetAnimationSync(repeatLeft, this.attackTimers.repeat);
+					}
+				},
+
 				// TODO: respond to target deaths immediately, rather than waiting
 				// until the next Timer event
 
@@ -2567,13 +2593,14 @@
 
 					// If the repeat time since the last heal hasn't elapsed,
 					// delay the action to avoid healing too fast.
-					var prepare = this.healTimers.prepare;
+					let prepare = this.healTimers.prepare;
+					let cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
 					if (this.lastHealed)
 					{
-						var cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
-						var repeatLeft = this.lastHealed + this.healTimers.repeat - cmpTimer.GetTime();
+						let repeatLeft = this.lastHealed + this.healTimers.repeat - cmpTimer.GetTime();
 						prepare = Math.max(prepare, repeatLeft);
 					}
+					this.lastHealed = cmpTimer.GetTime() + prepare - this.healTimers.repeat;
 
 					this.SelectAnimation("heal", false, 1.0, "heal");
 					this.SetAnimationSync(prepare, this.healTimers.repeat);
@@ -2633,7 +2660,29 @@
 					if (this.GetStance().respondHoldGround)
 						this.WalkToHeldPosition();
 				},
+
+				"ValueModification": function(msg) {
+					// Restart the timer if the attack repeat time has changed
+					if (msg.data.valueNames.indexOf("Heal/Rate") != -1)
+					{
+						let cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
+						let cmpHeal = Engine.QueryInterface(this.entity, IID_Heal);
+						let healTimers = cmpHeal.GetTimers();
+
+						let oldRepeatLeft = this.lastHealed + this.healTimers.repeat - cmpTimer.GetTime();
+						let scale = healTimers.repeat / this.healTimers.repeat;
+						let repeatLeft = Math.round(scale * oldRepeatLeft);
+
+						this.healTimers = healTimers;
+						this.lastHealed = cmpTimer.GetTime() + repeatLeft - this.healTimers.repeat;
+
+						this.StopTimer();
+						this.StartTimer(repeatLeft, this.healTimers.repeat);
+						this.SetAnimationSync(repeatLeft, this.healTimers.repeat);
+					}
+				},
 			},
+
 			"CHASING": {
 				"enter": function () {
 					this.SelectAnimation("move");
@@ -4100,6 +4149,11 @@
 	this.UnitFsm.ProcessMessage(this, {"type": "PackFinished", "packed": msg.packed});
 };
 
+UnitAI.prototype.OnValueModification = function(msg)
+{
+	this.UnitFsm.ProcessMessage(this, {"type": "ValueModification", "data": msg});
+};
+
 //// Helper functions to be called by the FSM ////
 
 UnitAI.prototype.GetWalkSpeed = function()