The shoulders are worked in a variety of exercises- thus there is no need to have a single day solely based on them. When you bench, curl, etc the shoulders are involved in the movement. I tell you this to avoid overtraining, which would happen when you repeatedly exercise your muscles before they have fully recovered.
Splitting the routine this way allows you more regular training, as the day after training your pushing muscles are still recovering, you can utilise and train the pulling muscles.
I would suggest doing a push/pull type of split in terms of how you work muscle groups.. i.e:
Work Back w biceps
Legs
Chest w triceps/shoulders
Working your chest directly after having shot your arms w a tricep workout the day before is unessesary and just wasting time to put it mildly. You would see significantly more gains if you group the proper muscle together rather than continuously training a "spent" muscle group.
His shoulders will be fine, as he does legs the next day giving his shoulders 48hrs rest. I disagree that you do not need to dedicate a full workout to shoulders. The shoulder is very complex and needs a variety of excersises to develop fully. Press, front raises, side raises, rear's and shrugs are classic shoulder routines.
OP, you have made great progress and now that you are enjoying working out, change it up. It is great that you watch your calorie content and limit to 2000, however you stated that may be comprised of anything as you only watch the total caloric intake for the day. If your diet could be changed to include a better mix of choice foods, you will drastically change again over the next 4-6mo's. Remember, now that you have lost the fatty your goals are changing. If your workouts are intense, on Tues and Thurs you are most likely burning well over 1000 calories during your 2hrs. Your body is most likely storing food rather than burning on these days due to the intesity of the workout, or even worse canabizing on muscle to feed itself. Now that you understand the benefits and enjoy working out, don't fear the calories (so long as we aren't talking about Fries, shakes, and chicken wings). Your metabolism and workout intensity will burn them off so long as you don't go on a binge.