I think in a commercial BIR where there may be a pot of base with oil on the surface etc where it is easy to swipe a spoonful into a curry when starting is a completely different concept to pre-prepared and stored seasoned oil, but for my moneysworth I learned not to Put garlic etc in it as it may go a bit off easier - I'm still chasing that BIR taste so stand to be corrected by more knowledgeable than me