Have a look and tell me if this is OK. Hard to decide when to go from cruising to when to descent!
See the dashed box in the corner of the chart. That is not drawn to scale (see chart text NOT TO SCALE). The enroute chart is always drawn to scale, so when you see such a region in a Jeppesen chart then rely on the enroute map position (but take the data such as speed/alt restrictions from the Jepp chart of course). MIGLO in this case.