This one drove me nuts for a long time
Found the the lowering flow control faulty ,it sits behind the main
Lift hose fitting in the aluminum valve body.
Look at the flow direction arrow when removing.
When the flow control goes bad the unit lowers slower than should
And the encoder doesnt count properly.
To check quick,if you have another picker handy
Put them side by side and lower them at same time
Both should be close to equil,the slower one is always the one with a faulty flow control.