Olivier,
In reviewing Ronnie's GSOD20 work on the wiki pages for these functions, I notice that the help page might be misleading.
GAMMA.DIST includes the statement "This function is identical to GAMMADIST and was introduced for interoperability with other office suites.". I believe that strictly, this is untrue.
The difference between the two functions lies in the C argument, which is required for GAMMA.DIST (as it is for Excel's function of the same name) but is optional for GAMMADIST (consistent with the ODF).
So while they are similar (and will give the same answers if you arrange for the C argument to be set to the same value), it is not true to say that they are "identical".
Can we fix this via gerrit?
Regards,
Steve