Fredxx explained :
That's not a typical setup. Most low pressure appliances operate at 28/29
mbar with butane and 37 mbar with propane with the appropriate regulator.

That used to be the case, but a few years ago caravans/motorhomes
swapped to a regulator mounted on the bulkhead, rather than the bottle.
The bulkhead one is a compromise between the two pressures. From the
bulkhead regulator then now use a high pressure pipe to the tank. The
bottle end of which, uses an adaptor for each bottle type.