Pat, are you trying to truncate releases or to restore them to the original full length?
Truncation of Front, Middle, and Rear ranks will make a big sound difference in Nancy. You'll hear it. Truncation on Close ranks saves some CPU but is hard to hear unless you only use Close, because the reverb is very soft.
Are you adjusting truncation in
1. Organ settings | Rank voicing... with the desired ranks selected and changing the perspective 1 release truncation parameter with the MSTR slider, or
2. Organ | Load organ adjusting... where you may truncate ranks at load time, or
3. Nancy's Settings tab with the division volume sliders (has no effect on truncation)?
In 1, sliding MSTR to a zero value means full releases, no truncation, but limited by any releases truncated at load time in 2. A truncated value in 1 is any small, positive number of milliseconds such as 17 or 35 or 50. I can't get the slider to hit a specific number, it jumps around for me, but anything less than 50 ms = 1/20 second is a very short release.
Please see page 206 of the Hauptwerk 7 Installation and User Guide. The circled parameter on that picture is the one you want to adjust.