We just played this last night, stopped to question this card and decided it meant one card per base played including itself because it just seemed like funny wording to use "if" when the card counts for itself. Why would "if" even apply when the card itself is a base? You will always have played a base this turn if the card is a base.
I don't agree with how I understand that you understand the card.
It means 1 card every turn that you play a base. Activating a base or having a base in play does not count. Only playing a base from your hand to the field counts, and you can only use the ability at most once a turn.