Just going through the Finished Projects (which seems an odd thing to call one's clients' sales).
The first one, a diet book, is published by Magni Book company. "Distributions are primarily through mass-market mail order, retail accounts, and television home shopping...We are also the exclusive licensed distributor for Tepota Hair Remover." I'm sure they're reputable, but I'd be surprised to hear that they pay advances.
The second, a 2008 mystery, is printed by Createspace, according to Amazon (the Project list calls it 'Terradan Works Publishing'. Author doesn't seem to have published anything else.
Three novels by two different authors, published by Medallion Press, a reputable press that sells, I think, mostly to libraries. Does it pay advances?
A 2005 memoir printed by iUniverse, as noted. No advance there. No other books found by this author.
A 2003 novel published by Novelbooks Inc, now out of business and mentioned
here for dubious business practices. Author has published nonfiction tech books, no other fiction.
Two novels from Double Dragon, a reputable epublisher that does not pay advances. I can't find these titles on DD's website presently, so I don't have a publication date for them.
A 2002 tech handbook published by McGraw-Hill. Author has not written anything else.
The remaining books all by the same author, including both the paperback and hardcover editions of one title as two listings - 2002 by Da Capo on its Amazon page, Perseus and Plenum on the Projects page.
Another of his books is a 1998 pamphlet of 33 pages.
Two are co-written, published by Aspen 1998 and Springer 1993.
I'm not seeing a steady income here, even for part-time work.
-Barbara