Sharing between spreadsheets

[Kevin]

In Spreadsheet A I have a list of tasks and values next to
those tasks. In Spreadsheet B I have totals of the values
from Spreadsheet A.

If I have Spreadsheet B open at the same time as A and
change something in A, B is updated. If I close B, change
something in A and then try opening B again, all the
values will be stuffed up by however many rows were
added/deleted.

I've tried locking the cells with $ and then again without
locking them. I've also tried going to the External Data
toolbar, but the only thing available is the 'Refresh All'
option which has no visible response.

I don't want to have to keep both spreadsheets open at the
same time to make changes if I can help it. Could you let
me know what I'm doing wrong?

Thanks,
-Kevin.