Buyng plots and building on them

There are 15 plots to be bought by the player. When the 1st plot is bought the lower border of the “Owned” area is correctly set as the lower Y border of the plot (exaple 320). When the player buys another plot (the adjacent lower plot) then the border doesn’t change but remains 320 (it should be: 480).
I use “Pick all instances of plot” as condition and “BuildBottom=LandPlot.BoundingBoxBottom()” as action.
Can anyone help?

There is condition called pick nearest

You can pick something nearest to Y -99999999 for highest possible object or y 999999999 for lowest