In BA settings, under the ladder tab, in the general ladder settings we have various options for showing the last traded volume.
We have 'Clear on every update', 'Clear after 300 / 500 / 750 milliseconds', and 'Clear after 1 / 2 / 3 / 5 seconds'.
A suggestion I think would be useful would be to add the option 'Replace when selection next matched' (or similar wording) thus leaving the green (drift), amber (same) or red (shorten) on the last matched odds until the selection is matched again at different odds.
This would be a useful (and final) visual prior to placing bets.