Why can't we use transformations for LS?
In addition to the UES for physical stats, we see two occasions where transforming gives you more LS.
As in the case of the gravity machine, where trunks transforming into SSJ made him move better (support his own weight), and we have a scene in which Goku was training with X tons of weight and managed to lift much more after transform into SSJ (boo saga).
Besides in super, with that fake black hole. Goku Base could barely stand up because of gravity, but when he transformed into SSB he was able to get up easily.
I think it's quite obvious that the transformation multipliers that go to strength, speed, etc., also go to the LS.