David: I what is happening here is that the feature that makes the £ unambiguous is the concave knee at the bottom left, but the current hinting loses this at 13/15 ppem by snapping to the vertical, rather snapping in the opposite direction (to be level with the left-hand extent of the cut-line). See the attached PDF for what is happening and the likely solution ensuring that the knee always remains concave.
David: I what is happening here is that the feature that makes the £ unambiguous is the concave knee at the bottom left, but the current hinting loses this at 13/15 ppem by snapping to the vertical, rather snapping in the opposite direction (to be level with the left-hand extent of the cut-line). See the attached PDF for what is happening and the likely solution ensuring that the knee always remains concave.