Very close, but your timeline is slightly off. "Blue" refers to the period when fluid builds up beneath the currently exposed eye scale, and the fresh one beneath it making the eye appear cloudy or bluish. The fluid build up is thought to help loosen the skin prior to shedding. After going "blue" (which is usually 5-7 days after the first signs of pink on the belly) the fluid recedes and the eye will appear normal again, in fact the whole animal looks pretty normal, it may be slightly dull or dark, and feel a bit rougher to the touch, but generally normal. 2-4 days AFTER coming out of blue is when you would expect to see the actual sloughing off of the skin. If they pass that time frame without shedding, that is when you want to start thinking of intervening. If they manage a partial shed (like you say with small bits) then it can safely be left until the next shed. If there is a complete circle of retained skin skin around the neck it has to be addressed before then as this could interfere with feeding, or retained eye caps since they won't be able to see very well.