intenseaty22,
I like the experiment and salute you for sharing your results with AGN. Shooting slugs at lower powers is definitely less explored than shooting them fast and faster(plenty of info from people doing that already).
I think the best applications for shooting slugs(instead of pellets) at low power are: 1) extended range to shoot at longer distances(when pellets run out of steam) with descent accuracy and 2) when it's windy(and pellets get blown all over the place).
For people who have a gun that is set up to shoot(pellets) at low power, if it's windy, then the distance at which you can be accurate is greatly reduced because the pellet gets blown so much by the wind. Same if you want to try a longer distance shot with an already slow moving pellet. It only has the BC to carry it so far down range.
If slugs are CLOSE TO as accurate as pellets at close distances(or in strong wind), AND are more accurate than pellets at medium to longer distances, then MAYBE it would be advantageous to use them in those situations(where a pellet doesn't work as well).
At low power, they MAY not have the PRECISION(tight groups) of a pellet, but they may prove to be more ACCURATE(you can hit what you're aiming at) at longer distances and/or when it's windy.
More testing(in the wind and at longer distances) would be needed to determine whether or not shooting slugs at low power would be of benefit.