I read through older posts about Lucas Heavy Duty Oil Stabilizer but they are outdated. So I emailed the same guy (John Mingus) who had replied to a question in this thread from 2005 to find out more and this is his reply to me:

Hank,
Thanks for looking to Lucas for lubrication solutions.
In regards to oil treatment your rotary engines are very sensitive to
viscosity changes so our recommendation is to go with a 10% treatment of
the oil capacity with Lucas Pure Synthetic Oil Stabilizer. This product
will deliver beneficial increases in both lubricity and film strength
without adding a negligible shift in viscosity. These are two major
benefits but you'll also gain dispersants that will keep the engine clean
and free of deposits if used over a long period of time. It does not lead
to foaming as reported in other postings on the internet.
Lucas markets 3 fuel treatment products - Lucas Upper Cylinder Lubricant,
Lucas Safeguard Fuel Treatment and Lucas Deep Clean Fuel System Cleaner.
Upper Cylinder Lubricant adds lubrication to the fuel and lifts carbon
deposits keeping the system clean and lubricated.
Lucas Safeguard Ethanol Fuel Conditioner neutralizes the chemistry in all
Ethanol fuel that leads to corrosion because of the dance between Ethanol
and water. It also stabilizes gas for 4 to 6 months.
Lucas Deep Clean Fuel System Cleaner uses a very friendly solvent to
dissolve problem deposits. It's a very good product to use 4 or more
times a year for a thorough cleaning or to prep for an emissions test. It
is friendly enough to add to every fuel fill but it's more economical to
use it occasionally and Upper Cylinder Lubricant 24/7.
I hope that this about covers all your questions.
Best regards for a Merry Christmas,
John Mingus

Take it for what it's worth, but since it's a response from the manufacturer and more up-to-date than other postings on the same topic, I thought I'd share it with you here.

 

That's interesting, thanks.