It's not "trying to pretend." If the rules don't say something then the rules don't say something.

Potions in 3.xed are low-level spells made into potions; there are no more restrictions on drinking a Potion of Reduce Person and a Potion of Haste than there are on having someone cast both Reduce Person and Haste on you.

(Don't know whether some other edition eliminates spell stacking. Indifferent to this lack of knowledge. 5ed remains unimportant.)