diff --git a/chiptune_player/README.chiptune b/chiptune_player/README.chiptune
index efb8536b..630661ce 100644
--- a/chiptune_player/README.chiptune
+++ b/chiptune_player/README.chiptune
@@ -463,21 +463,21 @@ lzma/diff:		  7257 bytes
 
 
 
-Timing:
-=======
+Interrupt Timing / AY write latency:
+====================================
 	Originally roughly 1500 cycles from start of interrupt
-	to all registers being written.
+	to all AY registers being written.
 		1500
 
 	Moved clock to after, near the visualization stuff, more like
 		1378 = 13+ (105*13)
 
-	Moved to load frame data at end of IRQ instead of begin
+	Load frame data for next time at end of IRQ, instead of begin
 		1029 =	13+2+(78*13)
 
-	Moved to load frame data at end of IRQ instead of begin
+	Inlined the mockingboard write routine
 		873 =	13+2+(66*13)
 
-	Only write registers than change.  Added 6 per loop
-		951 worst case
-		299 if only one reg changed	= 13+2+(18*13)+50
+	Only write registers that change.  Added 6 cycles per loop
+		951 worst case			= 13+2+(10+5+50+7)*13
+		304 if only one reg changed	= 13+2+(18*13)+55
diff --git a/chiptune_player/interrupt_handler.s b/chiptune_player/interrupt_handler.s
index e0912514..2c21091d 100644
--- a/chiptune_player/interrupt_handler.s
+++ b/chiptune_player/interrupt_handler.s
@@ -50,7 +50,7 @@ mb_write_frame:
 mb_write_loop:
 	lda	REGISTER_DUMP,X	; load register value			; 4
 	cmp	REGISTER_OLD,X	; compare with old values		; 4
-	beq	mb_no_write						; 2/3nt
+	beq	mb_no_write						; 3/2nt
 								;=============
 								; typ 11
 
@@ -66,7 +66,6 @@ mb_write_loop:
 mb_not_13:
 	sta	MB_VALUE						; 3
 
-
 	; inlined "write_ay_both" to save 12 cycles
 
 	; address