Australian Indian Restaurants use different gravies for the different "families" of curries, so there will be a butter gravy, a nut gravy (cashews or almonds), a vindaloo gravy and a standard onion gravy.
Perhaps what Steve is also referring to is that Aussie restaurants nearly all have an all you can eat buffet night once or twice a week for $20 or more where they will have 8 or more curries set out in a bain marie with accompaniments, sweets, chappatis, bhajis, raitas, Naan pieces etc. You just serve yourself and when a bain marie section runs low they just top it up out the back and replace (or at one place I know they just bring out a ghee bucket full and pour that straight in

)
Edit: and the Vindaloo usually has a warning on it. ;D
The Indian stalls in the Shopping Mall food courts are also set out like that. However for takeaway or table menu service on the non buffet nights they always seem take around 20 mins so I expect they are cooked individually.