TARGET_Y
%<\AcObjProp Object(%<\_ObjId 1925136928>%).InsertionPoint \f "%lu2%pr3%pt2">%

ORIGIN_Y
%<\AcObjProp Object(%<\_ObjId 855456944>%).InsertionPoint \f "%lu2%pr3%pt2">%

TARGET_Y - ORIGIN_Y
%<\AcExpr (%<\AcObjProp Object(%<\_ObjId 1925136928>%).InsertionPoint \f "%lu2%pt2%pr3">%-%<\AcObjProp Object(%<\_ObjId 855456944>%).InsertionPoint \f "%lu2%pt2%pr3">%) \f "%lu2%pr3%ct8[0.001]">%


; Finding the ObjID
(vla-get-ObjectID (vlax-ename->vla-object (car (entsel "\nSelect entity: "))))