When retuning the TV program list, the "smart" option is supposed to preserve customisations made to the list. However I find that, while locked and skipped channels are preserved, any changes I've made to the channel numbers are restored to their original defaults.
This is highly frustrating as I have moved BBC 1 HD (101), for example, to channel 1 where its non-HD equivalent was, but after a rescan they move back to their original places.
Please allow the preservation of custom lists when retuning. Perhaps if a conflict occurs when a new channel is found, ask the user which channel they would like to occupy that slot.