Shoulder of lamb: correct temperature and time?

We received the following question in the “Ask the chef” section:

I have seen on the cooking charts that a shoulder of lamb should be cooked at 80 degrees for 18 hours while another states that 75 degrees for seven hours. This all seems very complicated to me. Is this an error or is it correct?

This is how our chef Enrique Fleischmann answered.

The times and temperatures of different recipes largely depend on the type of meat to be cooked. Shoulder of lamb may have different times and cooking temperatures because it depends on several factors such as: type of lamb (suckling or older lamb), the lamb’s diet, the cut of lamb (shoulder or leg), if it has been marinated or seasoned, etc. On the charts, the different cooking methods are also due to one of these reasons. Furthermore, these times are standardised for a particular type of finish, so each of these times will result in a different texture and application of the product.

The times and temperatures in our charts are to be used as a guide. Taking them as a reference, each cook must find the appropriate times and temperatures for their recipes.