Help with Auto Bed Leveling!

I configured Marlin for Auto Bed Leveling. Now in response to G29 in Pronterface I get:

SENDING:G29
Bed x: 30.00 y: 180.00 z: 6.94
Bed x: 30.00 y: 70.00 z: 10.09
Bed x: 170.00 y: 70.00 z: 13.27
echo:endstops hit: Z:13.27

As you can see the Z offsets go in increment of about 4mm and show unleveled bed. At the same time my bed is perfectly leveled and individual G30s return the same offsets

What am i missing here. I appreciate any ideas!
Thanks!

I think someone had a similar issue in the "Auto Bed Levelling - Check this out!" thread.

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MakerFarm 8" Prusa i3v
RAMPS 1.4
0.4mm E3D v6 for 1.75mm

Here is what it looks like with greed and 4 pints of probing:

SENDING:G29
Bed x: 30.00 y: 70.00 z: 12.34
Bed x: 80.00 y: 70.00 z: 15.99
Bed x: 130.00 y: 70.00 z: 19.59
Bed x: 180.00 y: 70.00 z: 23.49
Bed x: 180.00 y: 113.00 z: 27.14
Bed x: 130.00 y: 113.00 z: 30.96
Bed x: 80.00 y: 113.00 z: 34.64
Bed x: 30.00 y: 113.00 z: 38.47
Bed x: 30.00 y: 156.00 z: 42.44
Bed x: 80.00 y: 156.00 z: 45.75
Bed x: 130.00 y: 156.00 z: 49.41
Bed x: 180.00 y: 156.00 z: 53.00
Bed x: 180.00 y: 199.00 z: 56.26
Bed x: 130.00 y: 199.00 z: 59.96
Bed x: 80.00 y: 199.00 z: 62.96
Bed x: 30.00 y: 199.00 z: 66.54
Eqn coefficients: a: 0.00 b: 0.34 d: -5.65
planeNormal x: -0.00 y: -0.34 z: 1.00
echo:endstops hit: Z:66.54

I had a similar issue to this, I discovered that my max speed for the Z axis was set too high, and during the bed leveling I was missing steps when it tried to move the head up.