STW (string_expression) not Returns the (real) width

[Anonymous]

How to make, that the length of a line of object at dragging changed correctly - according to command STW (string_expression)?

!Master Script
n = REQUEST ("Elevation_dimension", "",ed)
ePOSy=STR (ed,SYMB_POS_Y)
unID=0
HOTSPOT2 0, 0, unID, tx, 129 : unID=unID+1
HOTSPOT2 tx, 0, unID, tx, 2 : unID=unID+1
HOTSPOT2 -1, 0, unID, tx, 3 : unID=unID+1
line2 0,-1,0,1
line2 0,0, tx,0
text2 tx-STW(ePOSy)/1000 * GLOB_SCALE,0, ePOSy

!Parameter Script
VALUES "tx" RANGE (STW(ePOSy)/1000 * GLOB_SCALE,]

!Parameters
tx - Length