Differing M307 R parameter limits?

[achrn]

I think there are different limits to the M307 R parameter when the setting is in config.g than when set from console in DWC. It's not a big problem, I'm just reporting it.

Board: Duet 3 MB6HC (MB6HC)
DSF Version: 3.4-rc2
Firmware: RepRapFirmware for Duet 3 MB6HC 3.4.0rc2 (2022-02-22)
Duet Web Control 3.4.0-rc2

I have an enclosure heater configured, but no actual heater element, and to minimise the occurrence of heater faults I want to tell it the slowest possible heater parameters (that maximises the time for me to remember to switch the heater off if necesary).
This is because I want a thermostatic fan on the enclosure, and I want to be able to set the setpoint easily in DWC interface. Defining the enclosure heater lets me do that and see the temperature on the graph, even though the enclosure is not actively heated. Daemon.g checks the heater setting and sets the fan accordingly.

From the console, M307 H2 R0.02 B1 works fine:

However, in config.g it gives an error:

; chamber
M308 S2 P"temp3" Y"thermistor" T4701 B4266 C1.048787e-7 A"chamber" ; dangling thermistor
M950 H2 C"out3" T2                            ; create a heater, but not actually anything connected to this output
; try and maximise duration until heater fault occurs
echo "set H2"
M307 H2 R0.02 B1                              ; set lowest possible heating rate and bang-bang
echo "done"
M570 H2 P60 T99                               ; set very wide temperature excursion limits
M141 H2                                       ; set this to be chamber
M141 S35                                      ; set chamber to 35 - normal dont get too hot temperature

Are the parameter limits intended to be different in config.g compared to from the console?
The limit in config.g seems to be somewhere near 0.06 (0.06 works, 0.05 generates the error) c.f. the limit when command issued from the console is somewhere smaller than 0.02.