Neil Williams wrote on 18 September
2012 09:17:38 ...
wrote:

I hang my bags on the prongs for the store's plastic bags.

If you are having issues that may be why - the prongs are not weighed. So
when you put an item in, it registers weight of item plus weight of some of
your bag (which is heavier than one of theirs) and it gets confused.

You're better putting the full weight of your bag onto the base and having
the assistant correct so it balances.

Sainsbury's ask you right at the start "Are you using your own bags?",
and if you respond "Yes", it asks you to put your bag in the bagging
area, which then defines the starting weight. Seems to work quite well,
and without the need for an assistant to be involved.
--
Richard J.
(to email me, swap 'uk' and 'yon' in address)