Looks like the Castrol S100 is straight mineral oil, for new engine break-in.
Their AD100 looks to be Castrol's Ashless Dispersant oil.
In an already broken-in Lycoming, you want to run at least the Ashless Dispersant oils. If you also run oil that has the Lycoming additive in it, theoretically the cam lobes and lifters may last even longer. The Lyc Additive is mandatory for those oddball O-320-H2AD engines that Cessna put on certain 172's in the late 1970's thru the 1980's which had skinny cam lobes and a bad history of early cam and lifter problems that could lead to catastrophic engine failure.
The "normal" Lycoming engines (e.g. O-320, IO-320, O-360, IO360, etc) don't mandatory require the additive and can live and run just fine on regular ashless dispersant aviation oil (like the non-Plus Aeroshell, or Phillips "Blue Bottle" X/C 20W50), but the Lyc additive has definitely been known to help better prolong the cam lobes and followers/lifters lifespan in the long run, so it is a good idea to use it.