Piranha 95 and American History X are both Bill Smith.
Carnosaur 2 and Austin Powers: Spy Who Shagged Me are both William. I did not audit Austin Powers myself though, the other 3 I did audits for recently and trust them 100%.

FWIW, I have him locally as Bill, can't recall if that from numbers or not wanting to mix up actor/rapper Will Smith with him.

Human Nature --> Bill Smith

The Inspectors: William Smith
The Unnamable Returns: Bill Smith
Scarred City: William Smith
Riot: William Smith

Mysteries of the Bible: The Execution of Jesus

I profiled this one from scratch, so I'm sure it's Bill Smith.

Gun Crazy - William Smith
Jawbreaker - Bill Smith
Skipped Parts - William Smith

In 3 Ninjas Knuckle Up he's credited as Bill Smith for Dialogue Editor, Dialoge Mixer and Re-Recording Mixer.

I'm trying to establish the common name for Sound Re-Recording Mixer William or Bill Smith: http://www.imdb.com/name/nm0807448/.

Bill Smith: 56 Titles - 35 Titles confirmed
3 Ninjas Knuckle Up *confirmed by Corne
Alias: Season 4 *confirmed by reybr
All's Fair in Love & War
American History X *confirmed by bigdaddyhorse
American Strays
American Yakuza
Austin Powers: International Man of Mystery *confirmed by huskersports
Baitshop
Carnivàle: Season 1 *confirmed by hallo-marvin
The Climb
Coming Soon
CSI: Crime Scene Investigation: Season 3 *confirmed by huskersports
CSI: Crime Scene Investigation: Season 4 *confirmed by huskersports
CSI: Crime Scene Investigation: Season 5 *confirmed by huskersports
CSI: Crime Scene Investigation: Season 6 *confirmed by huskersports
CSI: Crime Scene Investigation: Season 7 *confirmed by huskersports
CSI: Crime Scene Investigation: Season 8 *confirmed by huskersports
CSI: Crime Scene Investigation: Season 9 *confirmed by huskersports
CSI: Miami: Season 1 *confirmed by huskersports
CSI: Miami: Season 2 *confirmed by huskersports
CSI: Miami: Season 3 *confirmed by huskersports
CSI: Miami: Season 4 *confirmed by huskersports
CSI: Miami: Season 5 *confirmed by huskersports
CSI: Miami: Season 6 *confirmed by huskersports
CSI: Miami: Season 7 *confirmed by huskersports
CSI: NY: Season 1 *confirmed by huskersports
The End of Violence
Escape: Human Cargo *confirmed by Corne
Eyes of the Serpent
The Gulf War a.k.a. Thanks of a Grateful Nation *confirmed by hallo-marvin
Human Nature *confirmed by Kluge
I'm Losing You
The Inspectors *confirmed by Sidrat
Jawbreaker *confirmed by Spab
Kermit's Swamp Years *confirmed by T!M
Leprechaun
Mysteries of the Bible: The Execution of Jesus *confirmed by CalebAndCo
No Dessert Dad, 'Til You Mow the Lawn
No Vacancy *confirmed by hallo-marvin
Phoenix (1995)
Piranha (1995) *confirmed by bigdaddyhorse
Precious Find a.k.a. Space Defender
Serpent's Lair
Session 9 *confirmed by Corne
The Sweeper
Thanks of a Grateful Nation
To Die, To Sleep
To the Limit *confirmed by Corne
Unbecoming Age a.k.a. The Magic Bubble
The Unnamable II: The Statement of Randolph Carter a.k.a. The Unnamable Returns *confirmed by Sidrat
Watchers III
Without a Trace: Season 1 *confirmed by Michael A
Without a Trace: Season 2 *confirmed by Michael A
Without a Trace: Season 3 *confirmed by Michael A
Without a Trace: Season 4 *confirmed by Michael A
Xena: Warrior Princess: A Friend in Need (The Director's Cut)
Yes: Keys To Ascension

William Smith: 34 Titles - 11 Titles confirmed
American History X *confirmed by bigdaddyhorse
Austin Powers: The Spy Who Shagged Me *confirmed by bigdaddyhorse
Black Scorpion
The Broken Hearts Club: A Romantic Comedy
Bully *confirmed by hallo-marvin
Carnosaur 2 *confirmed by bigdaddyhorse
Carnosaur 3: Primal Species
Changing Habits
Codename: Silencer
Corky Romano *confirmed by T!M
The Crazysitter
CSI: Crime Scene Investigation: Season 1 *confirmed by huskersports
CSI: Crime Scene Investigation: Season 2 *confirmed by huskersports
CSI: Crime Scene Investigation: Season 3 *confirmed by huskersports
CSI: Crime Scene Investigation: Season 4 *confirmed by huskersports
Dragonworld: The Legend Continues
The End of Violence
Executive Target *confirmed by Sidrat (he's credited as Sound Supervisor, not allowed because there's a Production Sound Mixer credited)
Guncrazy *confirmed by Spab
The Hired Heart
Human Nature *confirmed by Kluge
The Incredible Genie
The Inspectors *confirmed by Sidrat
Jawbreaker *confirmed by Spab
Johnny Mysto: Boy Wizard
Kung Pow: Enter the Fist
Leprechaun
Little Ghost
Made Men
The Midas Touch
Notes from Underground
Rage
Riot (1996) *confirmed by Sidrat
Scar City a.k.a. S.C.A.R. a.k.a. Scarred City *confirmed by Sidrat
Serpent's Lair
Session 9 *confirmed by Corne
Skipped Parts *confirmed by Spab
Skyscraper
Subterfuge
Things You Can Tell Just by Looking at Her *confirmed by Corne
Tiger Heart
To the Limit *confirmed by Corne  (he's credited as Sound Supervisor, not allowed because there's a Production Sound Mixer credited)
Universal Soldier: The Return
Walking Across Egypt *confirmed by antolod
Without a Trace: Season 3 *confirmed by Michael A