Dhcp client - "backoff-cutoff time" ignored?

[demux]

Hi,

I'm running pfSense 2.4.2-RELEASE-p1 (amd64).

On the cable link I wanted to adjust/lower dhcp client "backoff-cutoff time".  The GUI setting seems to be ignored.
I tried several settings but they are all ignored:  e.g. set 10 secs and dhcp interval goes up to 42 secs.

Did I miss something?  Are there any tips or hints?

Thanks a lot.
demux.