Hi,
One way to solve this would be to customize the fieldFactory (setTableFieldFactory(TableFieldFactory)) with an implementation that caches, potentially with weak references the created field. Then you could bind the value change listener into the field instead of the property.
Another solution would be to use some other event mechanism like to make your bean extend the good old
Observable
or make a wrapped version that extends Observable. This might actually be simpler in your case as your calculated value depends on more than one properties.
cheers,
matti