Jazz tuning style?

[Antares]

>Yesterday I tuned for a new client who just moved here (ohio) from the
>Boston area.  Just before I began to tune he asked me to give him the
>"jazz tuning", and NOT the "classical or pop" tuning.  It seems his tech
>in Boston offered him a choice from three tunings - jazz, classical, and
>pop.  In 21 years of tuning full time I have never been asked to do a
>"jazz" tuning, even though I tune for quite a few jazz players.  So I
>tuned the piano as I always do and he was very pleased, but I thought I'd
>throw it out to the list to see if any light can be shed on this. 
>Anybody have any thoughts on what exactly he may be referring to?  It WAS
>April 1, but he insisted he was not pulling my leg....
>
>Mark Potter
>bases-loaded@juno.com
>

Maybe a tuning with in every unison one string "slightly" off?
It makes a tuning edgy and the overall sound a bit louder,

I have once heard a Japanese tech demonstrate this, but I do not agree with
this method.
(The Japanese tech only showed it to give an example of a method to improve
loudness and make a tone a little more lively).

The funny thing is, that the result resembles the tuning of a Bechstein
treble because of those Bechstein false beats.

Antares