"She killed X, Y, Z for dumb reasons" is not a counter to "She was aiming at a very weak target, thus she shouldn't be using her full strength".
Being stupid and killing for petty reasons does not equal "will use her full strength to accomplish these murders". Your fly example might be seen as "overcompensates for weak opponents", but that doesn't mean she'd use her full strength either, just more than what she needed.
Slamming a 2 ton old lady into the ground is not justification for Tier 6 Attack Potency, regardless if its SS or LS. He never overpowered her, and the act of overpowering would be LS only anyway.
"wounds"? We'll have to wait for the anime, because saying two very small panels, one of which
does not show wounds at all (see the 1015 scan) are showcasing more wounds, is also very unreliable. We could say it's dirt from literally being slammed into the ground. It is well known that assuming having "hashtags" around your body is not enough to conclude damage.
The "long time" part needs to go, two chapters is not a long time at all, and we have to reason to assume it is. Judging by the events, it'd be bold to claim 5 minutes even passed between 1013 to 1015.
She was striking a small child.
This is what happens when she strikes at full strength. (Referring to the shockwaves, which do happen even if only one party have/is using Haki)
Cognac is unreliable.