For anyone looking into this in the future, I think these might help too:
Continuous Effects cont.
6.3.3. Substage order is used if there are two or more effects in the same stage and is defined by the dependence and type of modification within each stage. For stages 1–6, substage order is to apply independent effects before dependent effects. For stages 7–8, effects are grouped into the following substages and are applied in ascending substage order... (dividing a numerical property (base ATK damage in this case) is one of the substages)
6.3.3a If there are two or more effects in the same substage, the effects are applied using timestamp order (see Rule 6.3.4).
6.3.4. Timestamp order is used when there are two or more effects in the same substage and is defined by the timestamp of when an effect was first generated. Effects are applied in chronological timestamp order. If there are two or more effects with the same timestamp, the order is determined by the turn play