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AD9375 CLGC Relative Threshold

I am trying to correct configure CLGC on my custom board but there is something I don't get about Relative Threshold, from UG992:

"Value given by 100 × (Relative Gain Threshold in dB). Enforce this
threshold by setting tx1RelThresholdEn/tx2RelThresholdEn to 1 in
mykonosClgcConfig_t. When the CLGC is tracking at a given
gain level in steady state, this threshold represents the maximum
dB change allowed in currentGain from one CLGC iteration to
the next. ERR_16 is thrown if the relative threshold is violated.
Note that the steady state condition implies that the currentGain
and desiredGain values are fairly close because the relative
threshold test condition checks the currentGain against a bound
of desiredGain ± tx1RelThreshold/tx2RelThreshold limit.
Default value is 600 (6 dB)."

So what I don't get:
1) What is it's purpose if the check is done  between two different iterations?
2) Is it something that only rise a flag? Since i get error 16 if I shrink it too much but the clgc is still active
3) why should I want to use it? 
4) What should I monitor currentGain for?
5) And I didn't got the bound with desired gain, so this threshold does limit both current and power gain?