If you are using "Offset To Value", then the amount of offset is set in the "Offset" box in the data window and will always be the same amount until the value is changed. You might also note that the offset line is no longer a construction line and it will not be in the construction layer unless that layer has been set as the working layer.
The best way to create construction lines is to right click on the point where you want the line and at the bottom of the popup menu select "Construction Lines" -> Horizontal, Vertical, or 45°. The fourth item "Delete Constructions" will delete all construction lines. After the construction line is created select it and verify in the data window that it is correct, or adjust it as needed.
I just remembered that there is a construction line offset tool. The last icon in the Line toolbar has a submenu for the offset tool.