diff --git a/docs/development/PID Internals.md b/docs/development/PID Internals.md
index 5b921522ed..8e9e55af69 100644
--- a/docs/development/PID Internals.md	
+++ b/docs/development/PID Internals.md	
@@ -6,7 +6,8 @@
 
 `rcCommand` - `<-500 - 500>` nominal, but is scaled with `rcRate/100`, max +-1250
 
-`inclination` - in 0.1 degree, default 50 degrees (500)
+`inclination` - in 0.1 degree, roll and pitch deviation from horizontal position
+`max_angle_inclination` - in 0.1 degree, default 50 degrees (500)
 
 `axisPID` - output to mixer, will be added to throttle(`<1000-2000>`), output range is `<minthrottle, maxthrottle>` (default `<1150 - 1850>`)
 
@@ -16,14 +17,14 @@
 #### Leveling term
 ```
 error = constrain(2*rcCommand[axis], limit +- max_angle_inclination) - inclination[axis]
-P = constrain(P8[PIDLEVEL]/100 * error, limit +- 5 * D8[PIDLEVEL])
-I = intergrate(error, limit +-10000) * I8[PIDLEVEL] / 4096
+Pacc = constrain(P8[PIDLEVEL]/100 * error, limit +- 5 * D8[PIDLEVEL])
+Iacc = intergrate(error, limit +-10000) * I8[PIDLEVEL] / 4096
 ```
 #### Gyro term
 ```
-P = rcCommand[axis];
+Pgyro = rcCommand[axis];
 error = rcCommand[axis] * 10 * 8 / pidProfile->P8[axis] - gyroData[axis] / 4; (conversion so that error is in deg/s ?)
-I = integrate(error, limit +-16000) / 10 / 8  * I8[axis] / 100 (conversion back to mixer units ?)
+Igyro = integrate(error, limit +-16000) / 10 / 8  * I8[axis] / 100 (conversion back to mixer units ?)
 ```
 
 reset I term if
@@ -33,14 +34,30 @@ reset I term if
 ##### Mode dependent mix(yaw is always from gyro)
 
 - HORIZON - proportionally according to max deflection
-
-- gyro - gyro term
-
-- ANGLE - leveling term
-
+```
+  deflection = MAX(ABS(rcCommand[PITCH]), ABS(rcCommand[ROLL])) / 500 ; limit to 0.0 .. 1.0
+  P = Pacc * (1-deflection) + Pgyro * deflection
+  I = Iacc * (1-deflection) + Igyro * deflection
+```
+- gyro
+```
+  P = Pgyro
+  I = Igyro
+```
+- ANGLE
+```
+  P = Pacc
+  I = Iacc
+```
 #### Gyro stabilization
 
 ```
-P = -gyroData[axis] / 4 * dynP8 / 10 / 8
+P -=  gyroData[axis] / 4 * dynP8 / 10 / 8
 D = -mean(diff(gyroData[axis] / 4), over 3 samples) * 3 * dynD8 / 32
-```
\ No newline at end of file
+[equivalent to :]
+D = - (gyroData[axis]/4 - (<3 loops old>gyroData[axis]/4)) * dynD8 / 32
+```
+
+This can be seen as sum of
+ - PI controller (handles rcCommand, HORIZON/ANGLE); `Igyro` is only output based on gyroData
+ - PD controller(parameters dynP8/dynD8) with zero setpoint acting on gyroData