IBM says that the DMA controller does NOT support that address, so that's where the odd 1278-127F come from. Extended is bidirectional mode. I don't know what the other difference is. Note that the enhanced port is one bit more than a standard port.
Extended ports are two bits wider.
Go to the ECP Port's Resources and select the correct address and DMA Channel. It appears that DMA Channel 1 is used by DMA Arbitration Level 1. Am unsure if that's true, but it still works. Odd, but the IBM manual lists the enhanced mode, not the extended mode.